Tag: repair

#0034: Repair and analysis of a tap cartridge

Otto

#0034: Repair and analysis of a tap cartridge

Preamble

I recently had to repair a constantly dripping kitchen faucet, and thought that I may as well document it. Especially since I found the construction of the cartridges within the tap to be rather interesting. Although I must say that the title does make me feel a bit silly.

Tools and Materials used

Tools:

  • crescent wrench / 17mm wrench
  • nylon spudger / pry tool
  • phillips screwdriver
  • soft bristle toothbrush
  • plastic container
  • pipette
  • teaspoon

Materials:

  • petroleum jelly / plumber’s grease
  • vinegar
  • water

Tap cartridge inspection

I’d like to start by examining the water faucet’s cartridges themselves, as this information will be relevant later during the repair. The two pictured cartridges were taken from a quarter turn kitchen tap. This is a tap that only requires the handle to be turned 90 degrees around it’s axis, in order for it to go from a fully shut to a fully open state, and vice versa.

This type of cartridge is designed so that water flows into it from the central hole at it’s bottom inlet. This water then flows up inside it’s shaft, and through the two holes within the first ceramic disc. It is then diverted out through the two radial holes on it’s side via the second ceramic disc. At which point the water has a direct route to the faucet head.

This particular type of cartridge has two ceramic/plastic discs within it, that in conjunction with each other operate as a single water control valve. They do this by establishing a water tight seal between them; a press fit seal that is created by the two discs merely pressing against each other in a way that eliminates any gaps between them.

This seal is demonstrated within the video below, where you can see a suction effect take place between the two discs. This suction helps the two discs adhere to each other when wet. This is only possible due to the absolutely smooth surface of the first disc, coupled with the hollow cups present on the second disc’s contacting surface.

These two ceramic valve discs are both keyed to fit into their brass metal shaft in one particular orientation. This orientation has the bottom disc operate as a fixed or stationary valve. Whose job it is to split the ingressing water into two separate streams. It does this via the two distinct triangular quarter-circle holes within it. This lower disc is keyed to fit into the inner wall of the cartridge’s cylindrical housing in a way that makes it immovable.

Whereas the top disc is keyed into the rotating tap handle cylinder attachment. This allows the tap handle to control the rotation of the upper disc. This upper disc is cut in a way that either blocks the two water channels provided by the bottom disc when closed; or when open: diverts water from the holes of the bottom disc outwards to the radial holes in the cartridge housing. This water is then further diverted up and out of the tap for use.

The reason why it only takes a quarter turn to fully open the water channels of this type of cartridge: is due to the placement of holes and channels within these ceramic discs. The first (bottom) disc has two oppositely placed holes within it. Each taking up approximately a quarter section of the circular valve.

This quartering is then reflected within the top ceramic disc. Which consists of two opposing cupped flat plates, and two opposing angled wedges: which veer off to the radial holes within the brass cartridge housing. And since these channels take up opposing quarters of their discs – it only takes a quarter turn to either align both holes of the bottom plate with the upper disc’s water outlet ramps, which then allows water to pass; or with the flat plates, which then blocks the water at both holes.

Cartridge operation demo video

Valve operation demo video

Suction effect demo video

Dripping fault Analysis

Dripping fault cause theory

The fault that causes a dripping tap can be due to a number of different factors. Probably the most straight forward scenario includes water simply making it’s way around the rubber o-rings and/or water gasket. This could happen if the rubbers have gotten old or heat damaged, and started contracting or cracking as a result. Alternatively, they could’ve been disturbed or are otherwise not seated correctly in order to form an effective water barrier.

This means that whatever water does manage to get around these seals can then bypass the cartridge altogether and shortcut it’s way to the faucet head. The severity of the leak in this case would be directly proportionate to the ineffectiveness of the rubbers to seal out water.

Another issue could be within the cartridge itself. With water entering the cartridge and then passing through the cartridge valve by squeezing between the two ceramic disc plates due to an imperfect seal. This pressure fit seal between the two disc plates could be undermined by a number of different factors.

The most likely of which are a build up of limescale on the the ceramic discs themselves. Limescale is a broad term to encompass residual build up of the carbonates present in drinking water; such as calcium and magnesium carbonate. Water rich in minerals like this is often referred to as “hard water”.

Limescale build up on the contact surfaces between the ceramic discs, can cause them to then become uneven as the limescale adheres to them. Specifically the drip issue is caused because the valleys in this now uneven surface provide the water a small pathway across the pressure seal’s threshold when it is closed.

Another issue that could cause the valve to no longer function effectively is scoring of the inter-disc surface. Essentially scratches that then allow some water to pass through their valleys when the valve is closed. A likely cause of this could be something as basic as wear and tear. The two discs grinding each other down over an extended period period of time due to standard use. This happening with just the minor friction created from repeated opening and closing over time, eventually compromising the watertight seal as disc surface material is lost.

Before moving on, I should mention that this section is largely speculation. Basically educated guesses based on my observations during the disassembly. That being said these theories above are the one’s that I went into this repair with.

Dripping fault effect

A continuous drip may initially seem like a minor fault, because it is. However, this fault incurs a waste of resources. A slow but continuous one, that is hard to easily assess. Simply put it wastes water, and probably more than you might expect as well. Just because it only wastes a drop at a time, it doesn’t mean that it isn’t wasting a lot cumulatively. It just makes it difficult to easily see the totality of wastage.

Sampling methodology

Let’s try to get a rough idea of how much water is lost due to this fault. Note that this is not going to be very scientific. It is just a test to get a rough idea of water wastage. With that in mind, there are two discrete pieces of information that are required: 1) is the average water droplet volume; and 2) the number of water drips within a set period of time. In this case the sample time will be 1 minute.

I captured a single drop using a teaspoon. Then sampled it using a random plastic pipette that I had on hand. I repeated this a few times and found the droplets to be rather consistent in volume. Unfortunately, due to the pipette’s lack of precision, I was forced to visually estimate this volume between it’s labelled increments.

Collected observations

  • This leaky tap consistently provided around 13 drips within any one minute period.
  • With each drop having a volume of approximately 0.3 ml each.

Water drip rate and predictive volume lost

  • 1 minute: 13 drips @ 3.9 ml
  • 1 hour: 780 drips @ 234 ml
  • 1 day: 18720 drips @ 5616 ml (~5.6 litres)
  • 1 week: 131040 drips @ 39312 ml (~39 litres)
  • 1 month: 524160 drips @ 157248 ml (~157 litres)

Leaking faucet demo videos

Droplet sampling demo video

Leak conclusion

Interesting result. If a household either has a limited water supply (e.g. off-grid), or is on a metered supply where they pay for water by volume; then 157 litres lost in wastage in a single month by a single tap is not insignificant.

I hope this has illustrated how important it is to fix even minor faults such as this as soon as possible. 157 litres of water used could very well cost a metered household more money on the fault’s first month on the household’s monthly water consumption bill, than a complete cartridge replacement for that tap otherwise would have.

Repair process

Getting at the parts

First thing first. Common sense. I switched off the water by closing the main water valve for the house. This was located under the kitchen sink for me. This is an essential step in the same way as one would switch off the electricity before working on an electrical outlet, one needs to turn off the water before working on a water outlet. You’d think that was common sense right? But I have seen too many plumber fail videos online that say otherwise.

After giving the kitchen faucet a once over, and looking online I decided that the tap cartridges are the most likely suspects for the drip, so I set upon getting at them. Since I have never taken a kitchen sink tap apart before, I engaged in what I call an exploratory disassembly. Prodding and poking the device looking for hidden clips and screws.

To cut to the point: I used a nylon spudger to pry open the (metal coloured) plastic screw cover on each tap. I recommend using a plastic pry tool to avoid scratching the finish off of any part of the tap. Next. I unscrewed the phillips metal screws which attached each tap handle to the rotatable cartridge cylinder section below them. After setting aside the tap handles, I then removed the full cartridge assembly from the faucet housing using a wrench. As for disassembling the cartridges themselves, they come apart toolessly in-hand. That’s it. Easy.

Inspection

Like every repair, this one begun with a thorough inspection. A basic visual inspection did not reveal anything obviously wrong with either cartridge to my eyes. However once I disassembled both hot and cold units, I noticed that the internal plastic disc valves on the cold water side felt rough to the touch. Likely indicating a build up of limescale. Most notably this was even apparent on the surfaces between the two valves. And since these two surfaces come together to form the press fit seal that controls water flow: I concluded that this was likely the specific cause to this particular leak.

Limescale build up is nothing unusual for my particular location, as I do live in a heavy water area. However the odd part was that all the limescale build up was on the cold water side cartridge of our kitchen tap. With little to none on the hot water cartridge. This is really unusual in my opinion because I believe that higher temperatures should exacerbate limescale build up. The average water kettle should be a testament to this theory. However in this case the limescale build up was only sufficiently present on the cold water side.

A working theory I have concerns the on demand water heater which directly supplies this tap – a boiler which my household recently (1.5 years) had professionally installed. I believe that it has some-kind of water filter (or softener, or descaler…) that has been fitted to minimize limescale build up within the unit as it heats water. This means that the hot water provided by it to the tap would have less mineral contaminants (i.e. be softer) than the cold side. I would verify this, but it is not a pressing issue and not worth digging the unit out at this moment to confirm.

Cleaning the cartridge

Once I decided that it was limescale that was undermining the valves press-fit seal, I decided to take the already disassembled cartridges and submerged them into a vinegar solution. The idea is that the mild acid of vinegar will react with the alkaline limescale and dissolve it into the liquid solution.

After about an hour, I removed the parts and brushed them all down with a basic toothbrush in order to remove any loosened remaining debris. I did however take care not to scratch or score the plastic valves as any scoring would also undermine their ability to form a watertight seal; as this would allow water would pass through the miniscule divots that would be present on the seal’s contacting surfaces.

With regards to this method, I should note that I made exceptions for the rubber parts of the cartridges. The blue o-rings and red/blue rubber gasket. I just did not feel comfortable submerging them in an acidic solution for extended periods. I feared that it may affect the chemistry of the rubber material and ‘dry’ it out. Thus causing it to crack or split; and consequently be no longer effective as a waterproof seal. (FYI the pictures below are lying.)

Testing

After a quick rinse in tap water I decided to reassemble the cartridges and put them back into service for extended testing. Although the leaking was significantly reduced as it didn’t drip continuously as before: it still dripped regularly. This was tested by leaving an empty cup under the tap head overnight. I’d regularly find the typical coffee cup I used at least half-full come morning.

This lead me to surmise a number of scenarios:

1) That the water was making it in between the the plastic valve seals. Likely due to surface scoring caused by either my cleaning/brushing of the valve discs; or the limescale itself being ground into the discs as they operated over the years.

2) Water is making it’s way around the gaskets and o-rings, in addition to bypassing the valves. And that I have only remedied/alleviated one issue.

Greasing the cartridge components

With these conclusions I decided to then purchase some plumber’s grease. Thinking that it would be perfect for the application of assisting the plastic disc valves and rubber gaskets to form water tight seals. The Ebay listing for it explicitly stated just that.

However once the product arrived, I decided that I wouldn’t be testing it’s efficacy as I decided that it was not fit for use. The reason why: was that the little tin came with a whole host of warnings on it’s label. Warnings typically associated with poisonous chemical products.

Particularly the “Do not eat, drink, or smoke …” around this product warning gave me pause. Especially when coupled with the fact that the very vapours from this thing were an irritant. It emitted a vapour that was a mild irritant to the eyes and nose, smelling almost minty like the ointment “tiger balm”.

So despite the labelling assuring me that it is indeed appropriate for use within water faucets, I decided that this was not something that I wanted coming in contact with my drinking water – and ultimately ending up inside me. Maybe I am just paranoid. Maybe not.

Either way if an irritant chemical has warnings not to ingest it, and by using it for it’s intended purpose you are essentially guaranteeing ingestion. Maybe don’t use that chemical. Ultimately, it all just comes down to personal choice, and how much you trust anonymous Ebay sellers over your own intuition.

Personally I just found a substitute: Petroleum Jelly. A non irritant, non toxic chemical that routinely comes in contact with human skin and lips. So chances are good that it won’t do any harm if you accidentally ingest some with your drinking water.

Additionally unlike the plumber’s grease, the jelly can be used with rubbers like the o-rings and gaskets. I used to use some back in school within the science lab. A small amount was applied to the mouth of a bunsen burner’s rubber gas hose in order to help form a gas-tight seal between it and it’s brass attachment. I remember it even hydrating the dry red rubber of those hoses. Although I am pretty sure that petroleum jelly is also flammable so I’m not sure if that was a particularly safe application for it. :/

However within this application: my only concern with petroleum jelly is it’s longevity in the system, and heat resistance. However those are considerably less concerning than putting poison in a drinking tap. So after greasing everything up: the o-rings, the rubber gasket, and the plastic valve discs, then tighten everything down properly – I did note further improvement. Now the faucet barely leaks at all. Barely being the keyword here.

Jobs a gudd’un mate.

Post repair review

I left some time after the repair for observation before writing this review and it seems the leak is slowly returning after a month. A month of constant use keep in mind. I am still chalking it up as a success because this repair really only needed some basic tools and materials. The only consumables used are just household sundries like vinegar and pure petroleum jelly. So it can be done for next to nothing.

There are even more things I could do short of purchasing replacement cartridges, and that would be to use an additional o-ring under the main water ingress rubber gasket. This will put more pressure on the plastic disc valves. Squashing them together to form an even tighter pressure fit seal between them.

Although there are likely drawbacks to this, including and not limited to: firstly, a stiffer tap – the more downward pressure on the cartridge mechanism, the harder it would be to rotate it; and secondly, the higher pressure on the discs themselves would cause them to grind against each other more, and likely shorten their lifespan by promoting scraping of their contact surfaces.

Although if you are repairing it in the first place, chances are that they are already well towards their end-of-life, in which case this fix will extend it couple of months before they likely fail into a unrepairable state. At which point replacing the ceramic discs will be needed. Just my guess.

Closing thoughts

Not much to say here really, I surmised my thoughts on the repair itself within the Post repair review above. So I’ll go with a more personal note here.

I actually enjoyed looking at this tap cartridge more than I thought I would. It really is amazing what people are capable of creating through iterative design and mass production. It reminds me of the gaming concept of min-maxing: of getting the most out of the lest.

I mean look at the simple design and construction of this cartridge. It uses two plastic/ceramic discs to create a watertight seal by just pressing against each other. Undoubtedly the results of iterative cost cutting to the point of being adequate or acceptable, and little more.

I know that when I usually talk about cost cutting, especially when discussing mass produced goods: its usually in a negative light. That’s because the stimuli or catalyst for those tangential rants tends to be a product that is sub par, and in my opinion not fit for purpose. Products that I refer to as “factory fresh e-waste”.

However that is not the case here, these cartridges are fit for purpose. But they are also (in my humble opinion) built down to a price point. One that makes economical sense. Look at the bill of materials here for example: a brass housing and insert, a retaining clip for the insert, a metal washer, two o-rings, a water gasket, a metal screw, two plastic/ceramic discs, and maybe one or two additional miniscule hidden parts that I missed. That is a list that has been reduced to the absolute necessities and little more, but nothing less either. I admire the philosophy honestly.

Anyway, enough gushing about the tap. Since I repaired it: it’ll do that itself in a year or two ;). Upon looking up the Ebay prices for replacements, I noticed that they are very cheap. (At least the generic versions.) The average price for a set of two is £10; and if you wanted to repair your own two cartridges with a kit of replacement o-rings, gaskets, and ceramic discs, then that’ll set you back around £2.50. Very doable.

As a final note, if you found yourself confused as to why I kept referring to the cartridge discs as both made out of plastic and ceramic. Well, this is because the unit I was working on (pictured) felt like plastic to me. A hard somewhat brittle plastic.

However upon looking them up online, apparently they are all ceramic. I also wrote the repair section during the repair process prior to this; and I decided to leave it as plastic because that’s what I felt that material was while I was handling it. Although I am by no means an expert on such things, if the internet says that it’s ceramic then I guess it likely is.

Thank you for reading.

Links, references, and further reading

https://en.wikipedia.org/wiki/Hard_water

#0025: Modifying a pair of Game Boy Advance SP earphones into an auxiliary audio dongle

Otto

#0025: Modifying a pair of Game Boy Advance SP earphones into an auxiliary audio dongle

Preamble

This article will consist of a basic tutorial on how to create a Nintendo Game Boy Advance SP (GBA-SP) audio dongle using a broken third party pair of GBA-SP earphones. Additionally I will also provide some related commentary (ramblings) on the similarities between Apple and Nintendo; particularly the way they design their products, and the way that their fanbases receive them. So if you have any old earphones you got as a child and broke yet kept, or maybe even recently purchased as spares and repair? Or if you are inclined to hear me bemoan tribal consumers and corporate avarice. Well here you are.

Creating an audio dongle

The actual conversion is rather simple. You just need to first cut the earphones off; then connect the wires as shown in the pinout and wiring diagram below.

Pinout

Audio jack
1: left speaker positive
2: right speaker positive
3: common ground

GBA-SP port
1: right speaker positive (red wire)
2: closed loop switch
3: (pin absent)
4: left speaker positive (blue wire)
5: common ground
6: closed loop switch

Now that we have the broad methodology of what to do to create an audio dongle, I’d like to talk about a few specifics.

Closed loop switch

In the pinout diagram I labelled pins 2 and 6 as “closed loop switch”. What I mean by this is that there is continuity between these two pins. This means that they are electrically connected to each other. I believe they are configured in this way in order to act as a switch when the plug is inserted into the device.

The electrical connection between the two pins effectively closes an open loop within the device. One that terminates with these pins’ respective sockets. This loop is probably used so that the device can know when an audio peripheral has been connected. This is so that it can act accordingly, by for example switching off it’s built in speaker.

Where to cut the donor earphones cord?

This might seem like a rather simple question at first. However in order to answer it, I needed to answer a few other questions before knowing where exactly I wanted to make the cut. The most important question that needed answering is does the pair of earphones actually work properly, or are they broken somewhere.

Assuming that they have at least one fault somewhere within them, where is the fault? If you can not easily identify it, yet the earphones are still not outputting sound. Then perhaps the fault is hidden. In this case, it will mostly likely be either at the earphones themselves due to snag damage; or if you are unfortunate, it’ll be located near the plug due to something akin to repeated flex damage. Please note that I am just speculating from my experience with repairing headphones.

Once the fault is found, then you must make a decision. Repair the fault, or cut if off (if applicable). In my case the fault was at the left earphone itself. I didn’t probe further than identifying roughly where it was, since I had no intention of repairing something that far down stream. I did however consider whether or not I wanted to retain the inline volume dial. After some consideration I decided to remove it. The reason for this is that I feared that the relatively low quality of the componentry involved; such as the potentiometer, or the PCB and it’s solder joints may actually negatively affect sound quality. So I just snipped it off. Didn’t like it much anyway. It didn’t feel nice to use.

What type of plug or socket to terminate the cord with?

This question was primarily answered by the materials I had available at the time. I did not have an appropriate female 3.5mm audio socket available. However I did have plenty of male 3.5mm jacks on hand; including ones that were corded. In the end I went with a jack that was colour matched (black) and that had the smallest profile.

This male jack enabled me to plug the GBA-SP into an auxiliary port on a sound system should I wish to do so. Additionally when coupled with a female-to-female 3.5mm audio adapter, it enabled me to use headphones or speakers with the dongle. This setup basically gave me the same functionality as having an adapter that terminated in a female 3.5mm socket, paired with a typical male-to-male auxiliary cord.

Soldering the jack

When it comes to soldering audio jacks like these: the first actual thing I did was prepare the heat-shrink tubing for it. Selecting the right sizes and cutting them to length. I prepared two pieces, which I thought was sufficient at the time; however in hindsight I should have prepared three distinct pieces. One to isolate each line.

As it is, it has one to insulate the central shaft from the surrounding ground pad, and one to act as an outer cover; protecting all three wires and acting as a general guard against flex damage for the entire cord. It’s good enough, but it would be better in my opinion if the inner two wires were separated by more than just the enamel coating of the wire strands themselves, as I have left them. A smaller gauge piece of heat-shrink tubing on the inner terminal to cover it’s solder joint would’ve been better.

As for the soldering itself: audio jack terminals like the one pictured can be rather tricky to wire up and solder properly. The reason for this is due to a range of factors. Factors such as: the general fiddliness and fragility of the enamel wires themselves. Although more-so the close proximity of the jack’s terminals to each other, coupled with the convex curve and orientation of their soldering pads, is what adds difficulty; as the awkward angles involved can diminish dexterity.

Additionally, the presence of structural plastic insulation between the terminals, meant that a lower heat and a shorter soldering dwell time was needed. This in order not to damage the jack’s plastics with radiant heat from the work area. Otherwise the plastic will melt and warp the plug’s general shape and structure. All these various factors can make it difficult to solder in a reliable and repeatable manner. However practice and work flow optimisations will mitigate these type of annoyances as one gains experience in this task.

An example in which I optimised the process: was by preparing the wires for soldering by removing their enamel insulation. This is because prior to this: during soldering, the enamel coating on the wires sometimes wouldn’t burn off within the liquid solder blob itself; especially with the necessary (relatively) low heat and short dwell time. When this happened, it resulted in the wire not forming a good electrical connection and/or not bonding physically with it’s solder pad.

I chose to prep the wires by burning off a segment of their enamel coating using a lighter. This had to be done in very quick manner in order to not oxidise the underlying copper strands too much. Burning off the insulation in this manner allows me to quickly solder the wires into place without worrying about any complications from the insulation.

After removing a segment of insulation in this manner, I chose to attach the wires in a way that limited any exposed segments of wire present outside of the solder joint. This is to limit any exposed conductors. Consequently, the solder joints were close to their respective wires’ insulated ends, and only used the exposed segments to get a good electrical connection within the solder joint itself. After-which I’d snip off any excess exposed wire that preceded the joint.

Testing the cable

The attentive readers amongst you probably have noticed that my repair notes contain several resistance tests of the various lines. Most I ran while working on the device, those are the numbers closer to the hand-drawn diagram. Some of which have been struck out. Discount those. The ones of interest are at the bottom of the notes. Those are the results from the post repair test.

The reason for the final test was because I was dubious of the quality of the cables that I was working with. As well as generally dubious of audio cables of this calibre. Specifically, cables that consist of a small collection of loose strands dipped in (I believe) enamel for insulation; then interwoven with additional plastic or nylon strands for strength. They all look and feel fragile and cheap. Having said that however, I should say that a post repair test is a good general practice. Even when confidence in the repair is high.

As you can see the left speaker line has a end-to-end resistance of 10 ohms. Five times that of the right speaker line, and ten times that of the common return (or ground) line. The right and return lines have acceptable resistances in general, and accurate relative resistances to each other. I expected the return common line to have half the resistance due to the doubling of the lines. However, what was unexpected was that the left line was clearly an outlier in line resistance. This in my opinion is due to either the low quality of the cable in general, or a hidden defect I did not find.

It’s not ideal, but upon testing with actual sound, the loss of volume on the left line speaker due to it’s higher line resistance was not noticeable at all. So I just left it be. The effort necessary to track the fault that is adding the 8 ohms to the line, is not worth the reward of having perfectly balanced lines for a GBA-SP’s audio. I used to call it laziness not ploughing down these types of rabbit holes. However as I have aged, I have come to understand the diminishing returns on investments that this type of perfectionism offers.

  • testing during repair
  • post repair test

Completed mod demonstration

Related thoughts on Nintendo and their Game Boy Advance SP console

Now that we have created our own DIY audio dongle, let’s talk about why we needed to do this in the first place. In other words, why the Game Boy Advance SP doesn’t have a built-in 3.5mm audio port to begin with. In order to get at this answer, let’s first discuss a completely different technology company and it’s products. As to why, I’ll let you join the dots.

Many people today (2021) credit Apple as one of the most anti-consumer consumer technology companies, specifically with regards to their product design. Although there are numerous examples I could pick out, the one relevant instance here: is the removal of the generic 3.5mm audio jack from their 2016 iPhone 7 models. Anyone who pays any critical attention to this company probably came to a similar conclusion to my own. (Proceeds to pat self on back.) This naturally being that they did so in a bid to to sell first party audio peripherals at a premium. This being to their captive audience of fruity cultists. Cultists that would happily eat that up.

Why am I mentioning this in a Nintendo article? Well it’s because peoples’ memory is generally fickle and often mired with nostalgia; and the residual emotional attachments that it incurs. This leads them to holding double-standards when it comes specifically to childhood brands like Nintendo, often holding them to a lower standard of conduct than brands like Apple. These same people forget that their friend Nintendo did the same thing 13 years prior in 2003 with the incremental release of the Nintendo Game Boy Advance Special (GBA-SP) portable games console.

A games console that had no tangible advantages over it’s Game Boy Advance (GBA) predecessor other than a few quality of life (QoL) improvements. Both consoles played exactly the same games, however the SP boasted: an internal rechargeable lithium-ion battery, and an LCD backlight. For consumers tired of repeatedly buying new AA batteries for their GBA, or always awkwardly angling the unlit LCD towards a light-source whilst avoiding glare; these were improvements worth investment. Those of you who can read between the lines, might’ve guessed that this internal battery naturally required a specific Nintendo battery charger. A theme that they continued in later products such as with the Nintendo Dual Screen portable console (NDS).

However, a more apt feature of criticism in the iteration from the GBA to the GBA-SP, is the removal of the 3.5mm audio jack. Why did they do this you may ask? Well, now I could be wrong, but the cynic in me says that it was to facilitate Nintendo selling official audio peripherals at a premium, to their captive audience of pedantic neck-beards in waiting. That’s us mate.

Laughably, Nintendo’s official response against their audience’s pushback in 2003 was basically the same as Apple’s in 2016. They both said something to the tune of: that the new device simply didn’t have the space for a 3.5mm audio jack. Apple added some device waterproofing claims to this as well. But the core reason was the same: that there’s simply no space for it. Now shut up and buy our official peripherals. Peripherals that use the same port for both audio output and power delivery. So good luck using wired headphones and charging the device at the same time. Enjoy.

To cut it short. My point is that Nintendo has proven themselves to be as anti-consumer as Apple when the mood takes them. However it saddens me that their customers are prone to look at this company through rose tinted spectacles. Often even shouting down valid criticism, yet many within the community still consider themselves distinctly different from the stock of Apple enthusiasts.

That’s what happens when one thinks with their feelings. It’s tribal fanboy-ism at it’s finest. People for whatever reason forget that an individual’s relationship with a company or business like Apple or Nintendo, is strictly transactional. Nothing more. They are not your friends. A corporation does not have the capacity for camaraderie, or loyalty. Only the capacity to take advantage of such feelings in order to sell more to the same people.

Obviously, I am not talking about the entire consumer base here, just the vocal fanatics that seem to dominate public discourse. If anything a logical or reasonable person who likes the products of a particular brand to the point of becoming brand loyal; should ideally, be even more critical (than the average Joe) of their chosen company when it strays into anti-consumer practices. Due to their investment within the brand and it’s products. They likely would wish for them to stay good, more than a person who isn’t all that invested. But that’s not the world we live in. Instead the more invested a person is in a brand, it seems the more likely they are to tribally defend them regardless of circumstance. It’s sad really.

Closing thoughts

I know what you might be thinking, this article is nice and all, but it’s also almost twenty years too late. I mean in previous years getting a hold of an audio dongle for the GBA-SP might have been troublesome or expensive. Back when (the famously litigious) Nintendo were still protective of the console. However in 2021, one could easily purchase a NEW Game Boy Advance SP audio dongle from Ebay for less than a fiver. Since Nintendo doesn’t care much about protecting the rights to peripherals for a console that old (read unprofitable). Sure, the item that you buy won’t be an official Nintendo product, or even a notable third party contemporary brand peripheral, like Competition Pro. But it’ll work. Probably.

example of an unbranded Ebay adapter

To answer that question: Yes, yes you could. You could purchase an unbranded china special peripheral for your almost twenty year old console. Alternatively you could also make use of any old and/or broken first and third party peripherals that you may already have lying around, or even purchased in a mixed joblot or bundle. Essentially converting (basically) e-waste like that into a useful cable. One made to your exact use case and specification no less. Chances are your convert will also be better quality than a bought cable depending on what materials you use to make it.

Mine isn’t, I made mine from a pair of Competition Pro earphones. But still you get my point; I bet if you made yours from a pair of official Nintendo earphones (should you happen to have them), they might be better quality. As for making something for a specific use case: I totally use mine to blast Castlevania: Aria of Sorrow’s soundtrack, via my home sound system. I do it for maximum “immersion” during my midnight gaming sessions. I also want my neighbours to know that I am cool. The banging on the wall seems to indicate that they do.

Thank you for reading.

Links, references, and further reading

https://docpop.org/2016/09/apple-learn-nintendos-headphone-mistake/
https://arstechnica.com/gaming/2016/09/no-headphone-jack-nintendo-did-it-first/
https://en.wikipedia.org/wiki/IPhone_7#Headphone_plug_removal
https://en.wikipedia.org/wiki/Game_Boy_Advance_SP#Headphone_jack

#0023: Repairing short circuit damage within a ribbon cable

Otto

#0023: Repairing short circuit damage within a ribbon cable

Preamble

Sometimes you might come across damage within a ribbon cable similar to the example. The minor burn damage on the example featured was done by a liquid causing a short circuit between two exposed copper pads. As it burned, it created a break between an exposed pad, and it’s respective trace. Cutting the circuit in the process. The short also caused some of the other pads to oxidise, and some minor burning of the ribbon cable’s plastics. This will be a quick tutorial on repairing such a fault.

Please note: I have no images before the initial cleaning and prepping stage. This is because I was halfway through this repair, when I decided that it may be good to document it.

Tools and materials:

  • scalpel
  • tweezers
  • isopropyl alcohol
  • cotton earbuds
  • soldering iron
  • lead solder
  • copper strand from a wire
  • side cutters
  • multimeter

Step 1: Identifying and logging the damages

This should always be a first step before attempting a repair. The reason for this is that the initial pre-work cleaning, is likely to clean away a lot of contextual clues about the location and severity of all the damages. A good visual inspection and initial assessment can save time later on, due to not having to track down any circuit damage that got masked or hidden by cleaning.

Step 2: Cleaning the local area

First thing I did after identifying the location of any potential damage I wanted to repair, was to clean it. In this case I needed to first scrape off the more obvious patches of oxidation and burnt/melted materials using a scalpel. Then thoroughly clean off the pads of the ribbon cable using isopropyl alcohol and a cotton earbud. I paid special attention to the tiny burn hole next to the most damaged pad, making sure to remove any conductive materials from it by scraping it out thoroughly.

Step 3: Test to confirm faults

Using a multimeter in continuity mode, I tested for continuity between the pads surrounding the burnt spot. Perhaps it still contained conductors (such as pieces of the broken pad) that may cause a future short. After being satisfied that it did not; I focused on the particular pad that sustained the most damage, and tested for continuity across this pad and it’s respective trace to see if it was still connected. It was not. All other pads had continuity with their respective traces.

Step 4: Fixing confirmed faults

After identifying only a single fault; this being a break between a pad and it’s trace. I moved to repair it. Firstly I endeavoured to bridge the gap by just tinning across it from the pad to it’s trace. The thought process was that that the mere mass of the solder itself would be enough to bridge the tiny gap. It did not. After that initial failure, I decided that I required a bridging medium; something for the solder to adhere to. In this case I decided to use a single copper strand from a wire.

Using a scalpel, I removed some insulation from the ribbon cable trace above the broken pad. This was in order to have something on that side to comfortably solder the copper strand to. After which, I soldered the wire whilst using a pair of tweezers to hold the tiny copper strand down in place.

Step 5: Cleaning up after a repair

The next step involves cleaning up any messes I might’ve caused during the repair. In this case, whilst trying to initially tin the broken pad, I also tinned the neighbouring pads accidentally. In trying to remove the bulk of the solder, I caused further damage by starting to burn the plastic that the pads are set into. In the end I decided to just leave it be. The repair needed to be functional, not aesthetically pleasing. I did consider using a desoldering braid to remove all the solder, however I was very likely to cause more damage trying, so I opted to just leave it be.

In the end the after-fix clean consisted of just clipping off the excess wire with a side cutter and cleaning off any flux residue with an isopropyl dipped cotton earbud.

Please note: There is no electrical connection between adjacent pads. The burnt plastic between the pads just looks like solder. I told ya it was ugly.

Step 6: Testing the repair

Next. I performed a quick continuity test on the repair with a multimeter; both testing for continuity across the pad to it’s trace; and testing for a lack of continuity across neighbouring pads. These tests take basically no time to do and can set my mind at ease. I do these types of tests even when a visual inspection indicates that it’s not necessary.

The real test is putting the device back into service and seeing if it functions as expected. In this case the ribbon cable that I repaired was from a laptop’s integrated keyboard. Although the ribbon cable fitted more snugly into it’s receptacle or socket than I wanted. It still fitted and functioned properly. The keyboard was fully functional after this repair. Huzzah!

Closing thoughts

I apologise if this article came off as a little patronising; especially given the quality of the example repair, the missing “before” picture, and the fact that it contains mistakes front and centre. Generally, I find step-by-step guides like this one difficult to write, without sounding either needlessly pedantic or excessively didactic. Anyway, even if the exact specifics are not useful to you, I hope the general steps would be. Identify. Clean. Test. Fix. Clean. Test. Then Profit. That is if it works, if not: then go back to testing for faults.

Thank you for reading.

#0021: Repairing an LCD with missing segments

Otto

#0021: Repairing an LCD with missing segments

Preamble

This is a quick guide to repairing a specific fault found on undamaged low information monochrome numerical LCDs. Such the ones present within calculators. As such it will not go into detail about the functioning of LCDs in general, types of LCDs available, or any other information outside of the scope of simply repairing the missing displayed segments fault.

What is an LCD?

An LCD or Liquid Crystal Display, is a type of flat panel display. At its most basic an LCD operates by using the properties of liquid crystals coupled with polarisers. Polarisers are a type of optical filter that only allow light waves to funnel through them in a particular orientation. In other words, they remove light scatter; only allowing it through in a uniform manner. This, coupled with the liquid crystals’ property of altering their physical orientation when in the presence of an electric current; means that the narrow beams of light that make it into the crystal solution can either be allowed to pass through, or blocked, depending on the orientation of the crystals within the solution.

The specific type of LCDs we are dealing with are low information monochrome single line seven-segment displays. These types of simple LCDs are typically used in devices that predominantly output numbers. But may also display static symbols, such as the “E” in calculators for numbers that are too large to display without index notations. These types of LCDs are most commonly associated with pocket calculators. However they have been used with such devices as: alarm clocks, multimeters, solar charge controllers, battery monitors, household mains electricity meters; and I have even seen them used as a display on an electronic keypad lock.

I think this type of LCDs popularity is mostly due to it’s relative simplicity and low operating costs. It follows the KISS design philosophy. Keep It Simple Stupid. If a device would not notably benefit from a more complicated display, if all that it displays are simple numbers and basic symbols; then there is little reason to incur the (production and operating) costs of increasing design sophistication beyond this type of display.

As for the mechanics of how liquid crystals work, I like to (keyword) imagine a matrix of magnetic rods. At rest, the viewer can only see them from the top, and considering their microscopic size, this renders them essentially invisible. Whereas when a current is passed through them, the entire matrix of rod shaped crystals reorientate themselves to reveal the entire length of each of the rods. This greater surface area against the polarised light from the viewing angle, makes them appear opaque. There’s more to it than that, but that’s the general mental model I use to conceptualise the process. Although strictly speaking it isn’t accurate.

So how does a basic monochrome seven-segment LCD actually display information?

An LCD of this type is mapped with discrete segments. These primarily consist of seven dashes arranged in a number ‘8’ pattern. These are the core seven segments that are used to display numbers. Additionally LCDs have segments in the shape of static symbols; such as a period on calculator, or a colon on an digital clock.

Every discrete segment is given a set of electric probes. These probes are designed to allow a current to pass across the segment’s liquid crystals. This is how the liquid crystals within each individual segments are switched on and off. It operates in an analogous way to seven-segment LED displays. I.e. they both require an a electric current to be passed across each individual segment in order to activate it. Additionally, this electric current is controlled by a display controller IC (Integrated Circuit). Which translates any numerical values into display data (active segment and inactive segment map) that it uses to power it’s display accordingly.

example of an LED display
LCD segment map
segment circuit animation

Missing segments fault (on undamaged LCDs)

First of all, I specify that the LCD is undamaged because if the LCD you are attempting to repair is damaged, (e.g. has a crack across it); then chances are this fault is not the major contributor to your LCD’s malfunctions. That being said, missing segments on undamaged LCDs are likely caused by a break in the particular missing segment’s individual electric circuit supplying it.

Earlier I likened LCD seven-segment displays to their LED counterparts. This is because both require an individual IC controlled circuit that connects with each discrete display segment. Its just that with LEDs, its a lot easier for people to understand what is happening, when some of a displayed number’s LED segments fail to turn on. The failure to activate can be intuited due to a break in it’s branch of the circuit.

In this case the break in the segment’s circuit is usually caused between the LCD module and the underlying PCB; which hosts all device circuitry, including the display controller. This break usually occurs within or around the bridging material between the LCD and PCB. Namely the elastomeric connector (trade name: “Zebra strip”). This black and pink rubber like material is a soft electric conductive material that conducts electric signals across the naked pads of the PCB to the LCD and vice versa. It does this by having many tiny channels (or layers) of conductors and insulators, that alternate across it’s black strip. This black strip is then sandwiched with a pink insulator that runs the length of the outer sides of the elastomeric strip. This configuration allows the elastomeric strip to act like a large assortment of miniscule wires that electrically connect together whatever pads or traces that they touch at either of their ends.

The circuit break in this missing segments fault could be caused by two main things. Firstly, it could be due to an electric insulator getting in between the elastomeric strip and the exposed pads of the LCD and PCB. This could come in the form of a build up dust or grim, or even oxidation of the exposed PCB pads. To repair this, just clean all the pads and the elastomeric strip itself. I recommend using isopropyl alcohol and a cotton ear bud or cue tip. Just saturate the bud with the alcohol and scrub until it’s clean. Then reassemble the device and test.

Alternatively, this fault could also be caused by a separation between the elastomeric connector and it’s adjoining contacts. I.e. it has lifted off or away from the pads that is it supposed to be pressed against. This is usually caused by vibration. Typically, there will be a method of mechanically tightening or pressing the elastomeric connector against it’s pads. Such as a screw or adhesive, which with time and vibration (and maybe a little heat) can become undone enough that it allows the connector enough space to move away from it’s pads. To repair this, just re-tighten the screw or re-secure the elastomeric connector with tape if needs be.

The fault in the case with the example unit; I believe was caused by both a build up of dust between the contacts and the elastomeric connector, and also the connector physically separating from the LCD. The separation was caused by a loosening of the self tapping screws which held in place a bracing bar. This bracing bar applied pressure to the assembly consisting of the PCB, strip, and LCD, which sandwiched them together and kept them in place. That got loose, the strip moved slightly, and then dust got into the gaps that it created. After a good cleaning and tightening, it now works flawlessly.

Closing thoughts

When it comes right down to it, this is as simple as a repair really gets. No replacement of parts; just a basic disassembly and cleaning. It is essentially maintenance.

In my opinion, this type of repair is especially good for an aspiring repair tech with no confidence. The tools needed are basic, there are no additional parts (i.e. expenses) required, and the device being worked on it likely inexpensive; so there should be little in the way of consequences of failure. Such as fear of damaging a device, which may put people off from just ‘aving a go. Essentially the repair has little in the way of friction that may prevent a person from trying. It a good confidence builder.

Lastly, I just wanted to raise awareness encase you ever come across this type of fault in the future. It is easily repairable; and hopefully you’d be more inclined to at least give it a go, rather than discard the unit and purchase a new one as is usually the case for these types of cheaper mass market products.

Th-th-th-th-that’s all folks!
Thanks for reading.

#0020: Plastic welding techniques

Otto

#0020: Plastic welding techniques

Preamble

This is an introductory tutorial on welding plastics. The goal of this tutorial is to be a rather brief yet sufficient guide, that will allow the reader to be able to weld shut cracks and holes in plastic containers to the point of being water tight. It will cover welding technique, tooling, plastic types, PPE, and best practices. Everything an aspirant will need to effectively weld plastic containers.

Tools and materials

Tooling:

  • temperature controlled soldering iron or gun
  • (optional) fan

Materials:

  • appropriate donor plastic strips
  • (optional) duct tape or electrical tape

Personal Protective Equipment:

  • safety glasses
  • filter mask
  • thin rubber gloves

Core tool summary

As you can see the core tools and materials list is tiny. All you really need is a hot piece of metal to melt the plastic; and donor plastic material to flow into the various cracks and holes. This material is to reinforce and buttress the affected areas against any structural stress. That’s it.

Temperature controlled soldering iron

I specify a temperature controlled soldering iron (or gun) because you actually need relatively low temperatures to weld plastic; just enough to melt it, but not enough to burn the material. Most thermoregulated soldering irons would be too hot, because they are specced for melting solder. A material that generally has a higher melting point than many plastics. If the your iron is glowing red (even a little bit), then it’s probably a couple of hundred degrees (celsius) too hot.

Additionally, it would be beneficial if the soldering iron had a large thermal mass to enable it to maintain a stable temperature whilst it is in active use. I.e. actively transferring heat into the workpiece. A bit with a large surface area will also be useful, this is to effectively melt a good area of material at a time. Working with smaller bits makes the job more tedious. A smaller bit also concentrates the heat across a smaller surface area, which could cause heat spikes in the workpiece and consequently burn the local plastic. For the reasons above are why I chose to use a soldering gun with it’s widest tip rather than my usual general purpose soldering iron.

Plastic donor material

There’s not actually much to say about this. I like to make sure that the donor plastic is the same type of plastic as the item under repair is made of. This is to assist them in chemically bonding together more effectively. If you don’t want to purchase plastic donor strips like I have; you can alternatively just cut up similar items (i.e. items made from the same material) and use that. I have also seen many people use zip-ties as a donor plastic due to their convenient strip shape.

When selecting a donor plastic, look for a recycling symbol on the donor item (e.g. water bottle). Here it should have a few letters under it. These indicate what type of plastic the item is made from. Another thing to keep in mind when selecting a donor plastic is the food grade safety factor. To know whether or not a container is food safe, look for the knife and fork symbol. Specifically, when repairing a food grade container: do not assume that just because the donor plastic is the same type, as the food grade plastic container; that the donor is also food grade. Even if it initially is, the repair itself my change the chemical structure of the plastic to the point that it will now leech into any food (or drink) stored in it.

A good example is the container I repaired for this article. It was initially a food safe box, but now after the repair, even though it is now watertight again and I repaired it with the same type of plastic (PP); I would not use it for food, for fear of it leeching toxins into my foodstuffs.

common plastic types:

  • PET (Polyethylene Terephthalate) typically used in water bottles
  • PP (Polypropylene) general use plastic for containers
  • HDPE (High-density Polyethylene) typically used in milk bottles

Additional tools

Apart from the essentials, a fan will also help; both to blow any toxic plastic fumes away from you and to help cool the piece quickly as you work on it. Sometimes I find that as I work, an entire section of the container can suddenly soften to the point of almost liquefying, meaning that I will have to wait until it reconstitutes somewhat before work can continue. This however is an excellent state for moulding the pliable material to seal any cracks. Other than that, some duct tape may be useful to make the repair look more presentable and to give it a little more structural strength after a complete repair. Tape can also be used to hold the piece in place, as you weld the cracks.

Recommended PPE

As for PPE: I highly recommend wearing safety glasses and a filter mask. You really don’t want to risk globs of hot plastic flicking into your eyes accidentality. Especially since, if you are anything like me: chances are that your face is very close to the workpiece, in order to see every little detail. You also probably don’t want to suck up all those toxic fumes from any burning plastic either, so a cheap filter mask will help avoid that.

I would also recommend wearing a pair of thin rubber gloves. Although the plastic shouldn’t reach any serious temperatures before melting, a pair of gloves helps you comfortably shape any jellied plastic by hand; should you wish to do so.

Plastic welding techniques

I usually start by placing any loose container segments back into the gaps and holes that they broke out from. In a similar manner to welding metals, I then tack the loose segment into place. This is done by melting small spots across the circumferences of the segments; i.e. melting little bridges across the cracks. Do enough to keep each break out piece in place, or to stabilise a crack (in the case where there aren’t any breakout pieces, just cracks). For any holes where the original broken out piece has gone missing, you’ll have to use the sections of donor material to fill them in. I recommend melting the complete area into jelly, and shaping the mixed plastic mass into form. This is in order to properly blend the plastics into a watertight seal.

As an alternative to tack welds, some sticky tape can be used to hold a breakout piece in place while you weld. But this can get messy when you introduce heat near that tape. Depending on the type of tape you used, just some residual heat can cause the tape’s adhesive to turn into a sticky treacle that cakes the work area. The heat resistant kapton tape may be useful here, but it seems like a waste of resources using it for this application.

The general technique I employ in the actual repair, is by melting the donor strip onto the crack of the container. Then with the broadest side of the soldering gun’s tip, I scrap the extra material into the container’s crevasses. Like a plasterer covering a brick wall; pushing the plastic deep into it’s valleys. Then once one side is completed (exterior, interior), do the same for the other side of the fissure. That’s the short of it.

One thing to note however, this type of repair is not pretty. Although it can be very effective structurally. This is due to the repair involving melting and blending away the cracks. Then adding material to help remove any residual weak points. Weak points which tend to linger after a repair that doesn’t use any donor plastic.

The main reason for using donor plastic is because (in my opinion) plastic shrinks in the presence of heat. In other words, as you repair it with your soldering iron, the repaired plastic is actually smaller than what it was prior. This means that the repaired crack areas are actually thinner than they were originally. So consequently bolstering it with donor material is often necessary. Although admittedly it does make it look awful.

  • segment alignment
  • welding tacks
  • outer side done, inner side awaiting blending
  • inner side done
  • almost watertight after just initial fill and blend
  • container holds water well, despite drip leak

Demonstration of initial fix and seal

Closing thoughts

In summary plastic objects can be repaired should you wish to do so. It’ll require a soldering iron set to a low temperature and some donor plastic of the same type. Take care not to burn the plastic, and for goodness sake don’t breath the fumes in. Also remember that ideally any repaired food safe containers, should no longer be considered food safe. (However that could just be my general paranoia speaking.)

That’s all folks. Best of luck with your plastic welding adventures.

Thanks for reading.

#0013: Repair of a game controller with fatigued dome switches

Otto

#0013: Repair of a game controller with fatigued dome switches

What is a dome switch?

In order to know what dome switch fatigue is, we must first identify dome switches. Dome switches are buttons that utilise a dome made from silicon, rubber, polyurethane; or a similar material with the same elastic properties. This dome effectively acts like a spring and pushes the button back up when applied downward pressure is removed.

A typical dome switch will consist of several parts. These are: a (usually) plastic keypad key, an elastic dome, and a graphite pad. The switch key (or button) is mounted onto the elastic dome, additionally the graphite pad is attached to the concave or underside of this dome; and finally, this assembly is sat atop a patch of unconnected unmasked circuit board traces. These traces essentially function as switch terminals.

The idea is that when the downward force is applied to the key, the elastic dome is compressed; causing the graphite pad to press down on the unmasked PCB traces underneath it. This graphite pad actively bridges an electrical connection across these traces, due to graphite’s electrical conductivity.

When the connection is made across these traces, a logic level electric current (around 3.3 volts) is either pulled down to or pulled up from signal ground. It really depends on the IC (Integrated Circuit) chip that is managing and interpreting the keypad array as to the specifics. Anyway, the point is, essentially that is how the computer knows which buttons are pressed and for how long. After the pressing force is removed, the elasticity of the currently compressed dome material causes it to reset to it’s original domed profile. And in doing so it lifts the graphite pad from the traces and breaks the electrical connection.

Example of dome switches within a handset phone

Diagram of dome switch in action

image taken from: https://i.imgur.com/5K9Uy.gif

What is dome switch fatigue?

Dome switch fatigue, or more specifically dome fatigue: is when the domes within dome switches, develop a fault due to extended use that makes them no longer effectively reset their position. I.e. pop back up after they have been compressed.

The main symptom of dome fatigue is button sticking. In other words, when a button is pressed down, it either takes longer than it should to reset, or it stays down all together. This is assuming that the keypad is actually clean, as there are many reasons as to why a button might stick other than dome fatigue. Accumulated grease or oils, foreign objects (like food), and dust build up can easily cause button sticking.

Once the device has been opened, the domes themselves can be examined. Look for stress lines: thinner (often lighter) areas of material that can indicate structural weakness. I recommend comparing the suspect dome to it’s known good neighbours; adjacent domes from the same device that occupy buttons that don’t stick. Since they are from the same material stock and often from the same actual moulding as well (as is the case here), it can make spotting any actual stress signs easier. Common sense right?

As you can see in the example picture, there is a stress ring on the one of the four action button’s domes. This dome corresponds to the “A” button on an imitation USB Xbox 360 controller. Now I don’t mean to go on a tangent but I will say that imitation products like this controller are generally made to a price-point. I.e. the manufacturer cuts certain corners to bring the unit price down.

This is done in a bid to undercut the original product and sell itself as a budget alternative. In many cases the cut corners and lower quality product is mostly acceptable to the end user, as it is reflected in it’s price. However, these cuts tend to including: the sourcing of lower quality, less durable materials.

I believe this to be the issue here, although I haven’t had this controller for long. (Approximately a year.) I use this controller to mostly play platformers such as Splelunky. Since the “A” button is used to jump, it is by far the most used button; and it seems like over the time that I have owned it, I have just fatigued this particular dome. Either by some kind of repetitive flex damage (i.e. general use fatigue), or by just pressing too hard on it in moments of panic or frustration during play.

Example of “sticky button”

Example of fatigued dome

Repairing controllers with fatigued buttons

Sadly, an actual and effective repair of the dome itself is outside my capabilities. I just replaced the knackered dome with a fresh one. Well… a less knackered dome from a spares unit. As you can see I chose a third party “4 gamers” brand PlayStation2 controller as a donor unit. This is because that is all that I had on hand at the time. Additionally I am generally unwilling to purchase materials for a repair unless I have to. And to be honest, when it comes to repairing budget electronics such as this controller, it really is hard to justify spending any amount of money for materials, when one could spend a little more and purchase a new unit.

With this repair, I initially intended to replace the entire action button array (all four buttons), with domes from the spares unit. This is because the different types of domes will have different force pressure resistances, and bounce back elasticity. Which would lead to users experiencing different levels of tactile feedback or “button feel”.

At this level, I don’t mind much what the exact tactile feedback of the spares domes are; as I doubt specifying tactile feedback was much of a concern for this budget controller to begin with. Ergo this slapdash replacement wouldn’t necessarily denote a loss in overall device quality or user experience.

However I would mind if the feedback of the grouping of action buttons wasn’t uniform (or near enough). I.e. if one button was noticeably stiffer or mushier. That disparity in tactile feedback may actually become a distraction during play. It may even negatively affect a player’s performance; due to the player becoming accustomed to the tactile feedback of one button and then because of that either pressing to hard or not hard enough when they move onto another button (with a different level of resistance) in order to perform a different action. It may cause a misclick; either registering two inputs, if the new dome is significantly weaker/squishier or none at all if the new dome is significantly stiffer than the previous.

Unfortunately, I ended up just replacing the tired dome and using the rest of the three originals. Even though I have a picture of all four action button domes replaced on the controller. I dropped one on the floor shortly after that; and after 30 mins of searching. I just adapted to this strategy. In this case the new dome and the originals have similar (although not the same) level of tactile feedback to them. They aren’t different enough to be an issue. Not for me at least.

Spares unit

Application of spare dome(s)

Demonstration of device repair (before and after)

Original fatigued dome switch (green “A” button)

Although tactile feel can not be conveyed: notice the mushier, softer sound from the green “A” button when compared to the others.

Replaced dome switch (green “A” button)

The sound produced from the replaced dome is similar to the other three buttons, although they are not uniform themselves. There is an acceptable level of difference within tactile feedback across the buttons. The sound of the buttons when pressed reflects this.

Final thoughts

To sum up my basic ethos when it comes to repairing a device with fatigued domes. One, one has to replace the domes. As far as I can tell the domes themselves are irreparable. Two, When replacing the domes, it may be better to replace known good domes in a bid to get a uniformity of tactile feedback on all the buttons on a device, or at the very lest on a significant button grouping. Such as action buttons or directional (D-Pad) buttons. That’s the takeaway.

That’s all folks. Thanks for reading.

References, links, further reading

“Diagram of dome switch in action” gif taken from: https://i.imgur.com/5K9Uy.gif
https://www.mechanical-keyboard.org/advantages-and-disadvantages-of-mechanical-keyboards/
https://en.wikipedia.org/wiki/Keyboard_technology#Dome-switch_keyboard

#0008: Repair and Analysis of USB Micro type-B cables

Otto

#0008: Repair and Analysis of USB Micro type-B cables

picture of a dissected USB Micro B plug

If you are anything like me you probably have a sizeable collection of broken Micro USB cables neatly spooled onto a hook, or into a bag. Alternatively, you may even have them tangled into a rat king in a box or drawer somewhere … that is if you are a barbarian. You know who you are. So in an effort to lighten my ‘Spares & Repairs’ bin short of throwing things away (perish the thought!). I though it’d be good to repair a few. I know crazy right?

How and where do Micro USB cables typically break?

In order to repair something, we must first asses the damage. Where is it and how much is there? Well, with regards to the generic male USB 2.0 type-A plug to male USB Micro type-B plug cable: the damage is predominantly focused in the male Micro USB plug. Please note I will be using the term ‘Micro USB plug’ as shorthand for ‘male USB Micro type-B plug’ throughout this article.

picture of a bent USB Micro B plug

Initially, I used to get annoyed whenever a cable broke and rebuke the relatively delicate Micro USB plug as poorly designed. However, on reflection it is actually rather good that the weakest point in the pairing of the plug and socket: is in the plug and not the socket. Especially since after such incidents, the device socket tends to end up with little if no damage at all.

This is assuming that the majority of accidental breakages happen under certain conditions. These include: firstly, that the Micro USB plug is inserted into it’s respective socket on the device at the time. Whereupon it comes into acute mechanical stress by something akin a sudden impact (e.g. from a fall); or by a particularly vicious cable snag. This stress consequentially puts a lot of pressure on the connection between cable and device. Which in most cases causes the cable’s plug to give in before the device’s socket. Sometimes both are damaged if the impact is strong enough. However in a more typical scenario the plug breaks first, and in such a way as to leave the socket relatively unharmed.

Although my knee-jerk reaction is irritation whenever I perceive something as genuinely designed to break; I think in hindsight it is better that the cable’s plug is designed to break before the device’s socket. Since the cable is far easier (and consequently cheaper) to either replace or repair than the device would be. After doing some research, it seems that this is a conscious design decision (citation needed) and not one based on anti-consumer avarice, which (as a long time purchaser of consumer grade electronics) is the assumption that I have been conditioned to have in these types of scenarios. “Think Different”, Think Planned Obsolescence.

In this case, it is actually an iterative improvement on it’s predecessor: the Mini USB standard. Which suffered from port damage due to the shape and structural strength of the male plug, coupled with the fact that the retention and locking mechanism is located within the socket in the Mini USB standard. Whereas within the Micro USB standard, all such fragile and consequently breakable parts are located cable side. Having said that though, it still sucks when useful tools break so let’s try fixing them.

picture of a USB Mini socket. It shows the retention clips within the socket.
USB Mini socket

Structure of a male USB Micro type-B to male USB 2.0 type-A cable.

The male USB Micro type-B (or Micro USB) plug on average has typically four or five pads at it’s cable side and five interface pins that mate with it’s counterpart female socket. Please refer to the pin out diagram.

diagram depicting the wiring and pinout of a male USB 2.0 type-A to male USB Micro type B cable.

USB type-A:
Pin | Name | Wire Colour | Function
1 | VBUS | red | +5 volts supply
2 | D- | white | Data-
3 | D+ | green | Data+
4 | GND | black | Ground

USB Micro type-B:
Pin | Name | Wire Colour | Function
1 | VBUS | red | +5 volts supply
2 | D- | white | Data-
3 | D+ | green | Data+
4 | ID | no wire | ID pin for OTG functionality
5 | GND | black | Ground

Its simple really, pins 1 and 5 are used for power. Pin 1 supplies the +5 volts and pin 5 is it’s ground. Pins 2 and 3 are used for transmitting the data signals for communication. And finally, pin 4 is an identification pin, which is used for USB ‘On The Go’ functionality. It essentially tells the device that it is connected to, whether or not it is to act as a host system or a slave device when communicating with the device on the other end of the cable.

hyperlink: post_#0009:_Brief_guide_to_creating_a_USB_OTG_cable

Its a very similar setup with the male USB 2.0 type-A plug on the other side of this cable, except that it lacks an ID pin. Pin 1 is the V bus carrying +5 volts, pin 4 is the signal ground, and pins 2 and 3 are the negative and positive data pins respectively.

The reason the USB type-A plug lacks an ID pin is because any device that has a full sized female USB type-A port is already assumed to be the host system. Finding a peripheral device such as a keyboard (with the exception of USB pass-through), or mouse, or even a smart phone with a full sized female USB type-A socket is non-standard; as are the male USB type-A to male USB type-A cables needed for them.

The wikipedia.org article (“USB hardware”) mentioning this cable labels it as ‘proprietary, hazardous’. If I were to guess as to why that is, I’d say its because it allows the connection of two host systems (e.g. 2 personal computers), with no protocol to decide the role either system has to play. Additionally the input of power into a host system via it’s USB ports may cause damage (e.g. to it’s USB controller) because it may lack short circuit or input protection.

The Repair

Now that we have a basic understanding of the structure of the Micro USB plug and where the damage typically is. We can proceed to repair one.

Recommended tooling:

  • soldering iron
  • hot air station / heat-gun / lighter
  • hot-glue gun
  • precision knife
  • third hand clamps (handy grips, etc.)
  • testing adapters
  • female USB type-A socket breakout board
  • female micro USB type-B socket breakout board
  • multimeter
  • pliers

Consumables:

  • hot-glue
  • heat-shrink
  • Micro USB male plug kit
  • (lead-free or leaded) solder
  • rosin flux
  • electrical tape

P.P.E.:

  • safety glasses
  • light heat resistant gloves

The list above is just as a guide the the types of tools and consumables that you may need. Most of them are optional and are subject to personal preferences and circumstance.

Methods of repairing items

Most real world cable repairs I think broadly fall into one of the three categories or ‘methods’ I outline below. They all have advantages and disadvantages. Some allow for saving more time than money and other’s vice versa. Which ones are most appropriate to use will predominantly be based on the repair technician’s personal preference, available materials, and circumstances.

For example one could if one had two good candidate cables, splice them together into a working unit (i.e. method #1) using minimal tooling: just a knife to strip the wires, several unsoldered pig tail splices for the connections, and some electrical tape to isolate the USB wires from each other. And it would work fine. How long for? Who knows – but it will work for the moment and that may actually be enough. I give the example just to illustrate that things can be repaired a number of ways depending on either the person’s (in this case low) resources, and preferences; which can the run the gambit from the “just get it working for now” repair (shown above), to the perfectionist who wants a permanent repair that will outlast the product.

Method #1: splice two cables together

Probably the quickest method of repair involves simply splicing together two cables. This involves cutting the damaged parts off, then joining and soldering the four pairs of wires together according to their colouring. Red and red, green and green, white and white, black and black; and even sometimes the foil metal shielding if present. Simple. However, be mindful to first electrically isolate each of the four individual pairs, then cover over with a larger gauge heat shrink (for neatness) or electrical tape (for cheapness) to group everything together. I recommend a soldered Western Union splice as a method of joining the wires in the pairings. This is due to it’s relatively low profile and due to the mechanical strength of the resulting connection. Which means that in the case of any future tension on the cable such a sudden hard snag; chances are good that the new connection will not break. Nothing hurts my pride quite like having to repair one of my prior repairs. Consequently, I tend to do it properly the first time round.

hyperlink: post_#0003_Basic_techniques_for_connecting_wires

Now, there are obvious limitations to this method. The most pressing is that cables tend to get damaged in the same spot as each other. Especially when used in the same environment (or by the same people!), and in the same applications. So this method is not applicable in these cases. However in cases where it is applicable it is the shortest and easiest route to creating a reliable and viable cable. Primarily because it effectively bypasses the often finicky business of repairing the actual Micro USB plug.

Method #2: mend and make do (with salvaged spares)

So, like I mentioned above: most of these cables break at the same point. Namely, the male Micro USB plug. So unless you want to end up with a bunch of double ended (full size) male USB type-A cables. Splicing together the good ends of your broken cables isn’t going to do you much good.

So what now? Well first things first. We need to understand the extent of the damage itself. When you examine a broken Micro USB plug. If the metal outer shielding of the plug is present, then chances are that the metal plug itself is bent out of alignment by a fair few degrees across it’s broader sides. In this configuration, the state of the plug’s internal pins is unknown; or more to the point: it is unknown as to whether there is continuity across the pins (i.e. are they snapped or broken). By using a pair of pliers you can carefully correct the angle of the plug. I recommend doing this slowly before trying any other fixes. It needs to be slow, in order to give the delicate internal pins time to bend back into alignment. If the cable works after this, then that means that the internal pins were merely bent and not broken; and it also means that the repair is effectively done.

Alternatively, if after angle correction there is no continuity across the cable. Either by buzzing it out using various adapters and a multimeter — or just by plugging it into (hopefully inexpensive) devices and seeing if the devices recognise each other. Then it is time for a more invasive solution. I stipulate ‘inexpensive’ because many devices with USB ports don’t have adequate protection in cases of hard shorts to ground. It’d be pretty disheartening if a person, for example killed that USB 3.0 port on a their wiz bang gaming rig, because the wires were accidentally soldered incorrectly or shorted on that cheap shit cable they were trying to mend. I doubt that would actually happen, but better safe than sorry.

With a sharp knife, slice into the rubber or plastic sides of the plug. Create a broad slice from where the metal Micro USB plug’s base is (or was), all the way across the plug housing and up close to the strain relief. Peel back the rubber or carefully pry open the plastic to reveal the base of the Micro USB plug. Here you should be able to see where the four wires (for a data cable) or two wires (for a power cable) connect to the Micro USB plug’s base internal section.

This area of the cable: where cable meets Micro USB plug; tends to be either injection moulded with plastic or rubber, or filled with a type of hot glue. It is very easy to do more damage to the plug trying to get to it, then the damage that caused the cable to become inoperable in the first place. So if you intend to repair the Micro USB plug (rather than replace it), I advise proceeding with caution here.

Once you have made it to the base of the Micro USB plug. You many notice that the metal outer shield of the Micro USB is sometimes removable. If yours is, then it should be held in by a clip of some sort. Unclip it. Continue carefully dissembling the plug until you find the fault. In my case the internal pins broke as the plug was bent. I could try to re-solder them together or I could replace the Micro USB base with one from either another plug or a spares kit. Since this is the ‘mend and make do’ method, let’s say I went through the tedium of realigning the tiny pins and soldering them – and without melting their plastic housing or shorting them together no less … What I actually did was just replace the plug base with a known good one, for time and reliability.

Reassemble the plug. Then fill in any cavities you may have carved out on your way in, with hot glue. Close the cable head up, then wrap it in electrical tape. Done.

The strength of this method is that you can repair the cable without necessarily having to purchase additional parts. However the disadvantages are that it is very time consuming and finicky work. Work that could ultimately leave you with a plug that is structurally even weaker than the one you started with. So it may soon break again if not handled with care going forwards.

Make sure to do a through continuity test before pressing this cable back into service. Especially when it comes to testing for shorts across the pins. This includes pin 4, which depending on the testing adapter socket you are using, might be inaccessible. In this case I used to use crocodile-clip leads and needles as probes to test the pins on the exposed male plug without a female adapter. Although, I actually recommend just purchasing (or creating) a female Micro USB socket breakout board. It makes life so much easier than faffing about with a bunch of random low quality adapters or needles … which is what I used to do, and don’t really recommend. But sometimes you have to just use the tools in front of you.

  • picture of a dissected USB Micro B plug

Method #3: use a spares kit

This is probably the simplest actual repair after splicing two appropriate cables together. This method involves using a kit to replace the entire Micro USB plug assembly, including the strain relief. After cutting off and discarding the Micro USB head, remove the outer insulation of the cable, strip the the USB wires within and tin them. If the outer insulation is a fabric braid type, then melt the tip of the insulation with heat to stop it from unravelling.

  • picture of a bag of USB Micro B plug heads
  • picture of a USB Micro B plug in parts

Next up, slide on heat shrink (for cable bend relief), and then the Micro USB plug housing. This stage is probably easiest to forget. I can’t count the number of times, I have made a really nice soldered connection, only to undo it because I didn’t remember to slide on heat shrink beforehand. It’s funny, it only really happens on the more permanent joints, like the Western Union splice. I think its because I tend to be too preoccupied with making a good strong connection, that consequently: these types of things tend to slip my mind at the time. So take your time and do things methodically.

Just as an aside: heat shrink, in my opinion makes a good form of bend relief for a cable because it makes the cable a little stiffer along the length leading into the plug. This gives it resistance to bending to extreme angles, or allowing repetitive bend or flex damage to concentrate on a singular point on the cable. As for strain relief for the solder joints on the plug base: adding heat shrink to the cable does little. Id est it doesn’t prevent tugging force on the cable from exerting strain on the soldered connections between the cable’s wires and the Micro USB base’s pads. I’d carefully tie the cable end into a loose overhand knot (if it is of a thin enough gauge to do this), making sure not to cause any acute stress points in the wires as a result. This knot will act as a stopper against the insides of the Micro USB plug’s plastic housing. I am not sure whether or not this is generally advisable protocol, I am just stating what I tend to do. The loose knot offers some resistance to a tugging force as it tightens against the hole in the plastic housing. This in turn relieves the solder joints of some of the strain. Alternatively, filling the Micro USB plug’s housing with hot glue will also act as a decent form of (tugging) strain relief for the solder joints. These two methods do this by redirecting the pulling force away from the solder joints and into the housing and general superstructure of the plug.

Moving on. Now with everything in place, solder the USB wires to their respective pads on the Micro USB plug base. This includes the cable’s outer conductive shielding if present. In order to know which pads correspond to which pins: refer to any user guides or datasheets that may have been shipped with your spares kit. Alternatively test the continuity of the pads to the pins using a multimeter and a female Micro USB breakout board.

To connect the cable’s shielding: roll the loose strands into a cord. You may need to wrap this cord with another wire to extend it enough to reach the Micro USB plug’s outer metal housing. Which is a little further away than the USB solder pads on the example kit I have. I needed this extension to the shielding cord because when I cut the cable, it made all the internal wires and strands equal in length, so an extension was necessary in my case. After scratching off the finish on the part of the Micro USB plug’s metal housing that you intend to solder onto. Apply a small patch of electrical tape to insulate the USB wires from the shielding connection. Next, solder the shielding cord to the metal housing. You may need to apply solder to the twisted shielding cord to harden it and fuse the extension if necessary.

Now. Isolate the internal USB wires from each other, by injecting hot glue over and between the four wires. I use the electrical tape from before as a backing for this. I chose to have the adhesive side facing the USB wires, because I intended to wrap it around them at this stage. After this, pull the heat shrink into position then apply heat. Pull the plastic housing over the plug base and align the plug so that it is straight. I used the plastic cap to set the plug’s position. Once satisfied with the plug’s position within it’s plastic enclosure; remove the plastic alignment cap again and inject hot glue to fill any cavities between the plug base and the enclosure. Reapply the alignment cap. Then carefully apply some heat to the now closed plastic housing to make the hot glue within the enclosure melt into all the crevices and hold the alignment cap on. Be careful here because using too much heat can easily damage the plastic enclosure and alignment cap. Once that is done you are effectively finished.

  • picture of a USB 2.0 type A to USB Micro type B cable. The USB Micro B cable has been replaced with a plug kit.

Testing Phase

Although I tend to test at each discrete stage of a repair, for things such as bridged connections between pins or for consistent continuity across connections. I also recommend a final testing phase where we test the resistance of each wire using a USB 2.0 type-A female breakout board and a USB Micro type-B breakout board; or whatever the appropriate boards for the cable you are testing are.

The reason why I do this is to make sure that all the lines are of appropriate conductivity. In other words there aren’t any spikes in resistance in any of the lines that may cause problems when in use. This is especially true for data lines, where resistance will damage signal integrity. Although it is also important for power lines in use-cases involving higher current draws (around 2-3 Amps), such as those used in ‘fast chargers’. If there is sufficient resistance on the VBUS here it will retard the device’s ability to draw power across the cable.

Examples of improvised testing adapters

picture of a partially repaired USB cable inserted into some adapters for testing.
picture of 2 USB type A plugs. One has been stripped of insulation to be used for testing.

It’s generally good protocol to have a control test for comparison when testing your repaired cable(s). In this case I used a Samsung brand, model: U2 APCBU10BBE data cable that came new with a smart phone purchase. Please note: the control cable used here is not designed for higher current draws, it’s device needed a maximum of around 700mA to 1 amp when charging.

(Control) Samsung (U2 APCBU10BBE) data cable:
VBUS: 0.2 ohms
D-: 0.3 ohms
D+: 0.3 ohms
GND: 0.4 ohms
Shielding: none
Cable length (approx.): 1 meter

(Testing) Repaired w/kit yellow cable:
VBUS: 0.2 ohms
D-: 0.3 ohms
D+: 0.5 ohms
GND: 0.6 ohms
Shielding: 0.1 ohms
Cable length (approx.): 1 meter

(Testing) Repaired w/spares red braid (‘fast charge’) cable:
VBUS: 0.2 ohms
D-: 0.3 ohms
D+: 0.2 ohms
GND: 0.1 ohms
Shielding: none
Cable length (approx.): 2 meters

picture of a new USB 2.0 type A to USB Micro type B cable, connected to some breakout boards used for testing. This cable was used as a Control test.
picture of a spares repaired USB 2.0 type A to USB Micro type B cable, connected to some breakout boards used for testing.
picture of a spares repaired USB 2.0 type A to USB Micro type B cable, connected to some breakout boards used for testing.
picture of the USB type A female socket breakout board and USB Micro B female socket breakout board used for testing.
picture of a kit repaired USB 2.0 type A to USB Micro type B cable, connected to some breakout boards used for testing.

As you can see, they tested close enough that I feel that the cables that we repaired are of an appropriate quality, at least for me to have enough confidence to press them into service. Alternatively instead of using a control test for comparison, if you manage to find a datasheet for a particular cable you wish to replicate. The data from the datasheet can be used as a target instead. I just found it easier to see how my everyday cable fairs, then try to ape it’s stats. Consequently I do not have a concrete idea of what the resistance tolerances and acceptable margins are for these cables to maintain signal integrity while in use. But I am confident from the comparisons with the control cable that we are within them.

However, if say a cable tested (pulling numbers from my … hat) 15 ohms on a data line. I would inspect the repair, if it seems fine: then the problem could be with the cable itself. For example: such as in a wire where many of it’s hidden internal strands have broken due to repeated localised flex damage. So all the current is having to pass through just a few strands at that point, causing an invisible bottleneck. This should have been tested for at the initial stages of a repair when the cable was first cut and the wires exposed. But still, finding this fault at this stage, allows you to make the informed decision on how to go forwards, either demote it to a power only cable (and mark it as such), scrap it for parts, or find and fix the newly discovered fault.

Eventually, once you reach a stage where you are confident in a cable’s performance, the repair is truly complete and it is now ready to use. Done. This time for real. Thank you for reading.

References / Sources / Further Reading:

https://en.wikibooks.org/wiki/Serial_Programming/USB#What_is_USB?
https://en.wikipedia.org/wiki/USB
https://en.wikipedia.org/wiki/USB_hardware
https://en.wikipedia.org/wiki/USB_On-The-Go
https://en.wikipedia.org/wiki/USB_(Communications)#Signaling_state
https://www.ifixit.com/Guide/Micro-USB+Port+Replacement/73401
https://www.portplugs.com/how-to-repair-a-loose-micro-usb-port/
https://www.youtube.com/watch?v=36CKsP9YQ1E [why does USB keep changing – NostalgiaNerd]
https://goughlui.com/2014/10/01/usb-cable-resistance-why-your-phonetablet-might-be-charging-slow/
https://www.mschoeffler.de/2017/10/29/tutorial-how-to-repair-broken-usb-cables-micro-usb-including-data-transfer/
https://www.mouser.com/pdfdocs/HiroseZX62Datasheet24200011.pdf
https://www.howtogeek.com/670644/what-is-fast-charging-and-how-does-it-work/

#0002: Cleaning up after an alkaline battery leak

Otto

#0002: Cleaning up after an alkaline battery leak

picture depicting a stack of rusted and leaking double A batteries

This will be a rather basic guide on how to clean out a device after an alkaline battery leak.

Whenever I come across an old device, that for some initially unknown reason refuses to power on. Chances are, that someone left disposable alkaline batteries inside it, and that they have leaked. There are a number of reasons as to why people leave batteries inside devices. Predominantly: laziness, ignorance, or forgetfulness. There are also a number of reasons as to why these same forgotten batteries leak. Batteries with mixed charges, reverse charging each other, or a constant low current draw causing leaking; are but two examples.

Unfortunately, a more in depth look into what causes disposable batteries to leak is outside of the scope of this article. However it is something that I am interested in exploring at a later date. Check the further reading section of this article for the hotlink to that, when I eventually get round to penning it.

I cannot count the number of times I have opened the battery compartment of a device, that has been left in storage for a while; only to be greeted with a vented battery, rust, and the the blue-white fuzzy carpet of alkaline crystals growing out of it. Meshing into, fusing with, and corroding the negative terminal’s spring contacts. This infection then proceeded down the circuit and further into the device and onto more complicated/valuable components. In this regard, an unstemmed battery leak has the potential to brick a device.

picture depicting heavy alkaline battery leak on battery spring terminal

So, how do you deal with it? Well, if caught early and the leak hasn’t progressed far beyond the battery itself, and a bit of surface level corrosion on the spring contacts; then it is really not much of an issue. A quick wipe down with a damp cloth after disposing of the batteries, should suffice. I recommend using isopropyl alcohol to dampen the cleaning cloth, mainly because it becomes non-conductive very quickly by evaporating readily. It also doesn’t leave any contaminants like water might. However water is fine to use in a pinch; just make sure it is fully evaporated and that there is no substance residue left after cleaning; before you power up the device.

picture depicting very light alkaline battery leak on battery spring terminal

If the leak has had the time necessary to progress further into the circuit and deeper into the metals. That’s when you have to take more invasive steps in order to remove it. There are two main ways to deal with an advanced battery leak. Which one to use, largely depends on circumstance. The most important factor being whether or not the affect parts can be removed from the device.

Method #1: Acid Bath

The first method of remedy, requires the removal of the affected parts and the use of an acid bath. Removing the affected parts, will likely require de-soldering. Next, create a bath, of vinegar and water at a ratio of approximately 1:3. So 25% vinegar and 75% water, or thereabouts. This leaves you with a mildly acidic solution for you to submerge any affected parts within. Mix the solution well, then drop the parts in. Leave it for some time. How long for based on your own judgment. I recommend 30 minutes to a couple of hours depending on the invasiveness of the alkaline crystals into the metals.

picture depicting an acid bath (blue tub with vinegar-water inside it), and a pair of forceps

Remove the parts from the solution when you think that they have been in there long enough. At this point, they will require brushing down, to remove any stuck on materials. Use a strong bristly brush for this, something like a firm toothbrush will do. For those wondering, a wire brush would probably be overkill for this application, especially since the subjected parts would likely be rather small, and wire brushes are traditionally made for uses with larger items. Wire brushes will also likely remove the finish on the metal parts, that is if the acid bath hasn’t done so already.

picture depicting heavy alkaline battery leak on battery spring terminal

The main reasons why I recommend using a mildly acidic solution to counteract the alkaline crystals is: one, in order to minimise the severity of the reaction between acid and alkaline; and thus minimise the chances of additional corrosion or damage done to the metals in the process; and two, to minimise the chances of the acid removing or damaging the metal’s finish by reacting with it. It should be noted that plenty of parts in modern mass produced devices are made up of mixed metals, then given a chrome finish for uniformity.

picture depicting battery terminals with chrome finish removed by the acid bath

I should note that when I say ‘part’, I am referring to simple primarily metal constructs within devices; such as spring terminals or basic switches. I am not referring to more complicated components such as resistors, capacitors, transistors, or anything more sophisticated than those examples. This is because the acidic solution is very likely to compromise the internal structure or chemistry of any components submerged within it, if the leak’s corrosion hasn’t done so already. Bricking the component in the process. More on what to do with leak affected components mentioned later.

picture depicting two leak corroded battery terminals with chrome finish removed by the acid bath

After brushing all foreign materials off of the parts, dry them off, then wipe them down with a cloth laced with isopropyl alcohol. Continue until you are confident that you have removed all contaminants including traces of alkaline crystals and the acidic solution. Once this is done leave the parts to dry fully, before then placing them back into the device and likely soldering them back into the circuit they come from. That’s it, done.

Method #2: Acid Wrap

The second method of removing alkaline crystals is used when the affected part cannot be removed either from the device or it’s circuit for whatever reason. A good example of this is when a part is either welded, crimped, or glued into place; making it’s removal potentially too destructive to consider lightly.

picture depicting two spring contacts, one clean and the other covered in alkaline crystals
picture depicting two spring contacts, one clean and the other covered in alkaline crystals (front view)
picture depicting two spring contacts, one clean and the other covered in alkaline crystals (back view)

This method requires either tissue paper or cloth. Id est, something that can soak up liquid and cling to a particular structure without external pressure/force. I use tissue paper for this example. Soak the tissue paper in a diluted acidic solution; enough so that it has plenty of solution available but not enough that it drips excess. Then wrap it around the affected parts and wait for time, before removing it and brushing off any loose materials. Rinse and repeat until it looks done. Then clean and wipe down the part with an isopropyl laced cloth. Done.

You can adjust the ratio of vinegar to water to your liking. I still recommend a mildly acidic solution to minimise the severity of the reaction (and any damage caused from it), but the more acidic the solution is, the quicker it’ll dissolve the alkaline crystals off of the affected parts. From my experience a ratio of 1:1 seems to work out well.

Another tip for this method is to properly isolate the rest of the device from the part you are currently working on. This is done to avoid any accidental drips from the tissue paper or off-spray caused by brushing. Vinegar-water and electronic components are best left separated. With that in mind, I recommend using a plastic bag and tape. The plastic bag functions as a waterproof membrane and the tape holds it in place. Simple.

picture depicting two spring contacts, one clean and the other covered in light rust (viewed with chassis)
picture depicting two spring contacts, one clean and the other covered in light rust (front view)
picture depicting two spring contacts, one clean and the other covered in light rust (back view)

Dealing with components

Now that the basic method of cleaning metal parts has been explored, you may be wondering as what to do when the leak has reached more complex components. Well, the answer is simple. Try to remove whatever battery residue you can mechanically; i.e. just using a brush or a small chisel of some sort. Then de-solder/remove the component from the circuit. Test it appropriately. I recommend having both a multimeter as well as a multi-function tester on hand for this. If it is still within specification, solder it back into circuit; if not, replace it. There is not much one can do for any affected components beyond this. Once a capacitor or resistor is broken, it needs to be replaced.

Conclusion

As a final note, I should also mention that in a lot of situations: replacement of the affected metal parts is probably the more appropriate recourse to severe leak damage then repair might be. This means replacing spring terminals, and creating jumper wires as replacements for corroded PCB traces. This is because the repair can weaken the metal, leaving one with brittle spring terminals or a trace with more resistance in it than initially intentioned. However having said that, if you either can not remove the part, or don’t have the prerequisite replacements: then an ugly repair is better than no repair at all.

Sources/References/Further reading:

https://en.wikipedia.org/wiki/Alkaline_battery#Leaks

https://upload.wikimedia.org/wikipedia/commons/7/76/Alkaline_Battery_Leakage_Inside_a_Product.png

https://en.wikipedia.org/wiki/Isopropyl_alcohol