Haha this is epic level trolling. "Mutter mutter 15 minutes fixing a dodgy switch mutter mutter" "Really, here's 15 more minutes of me taking that switch apart... enjoy!"
Silver oxide is reasonably conductive, the black is silver sulphide, which is an insulator, or at least a poor resistor with 5V applied. Silver plated with a thin coat on the one side of brass sheet before being punched out and into the die to shape it. The more expensive uses stiffer and harder nickel, which is more resistant to corroding, and can get by in regular atmosphere with no coating on it, but yes for the best you want heavy gold plating on the disk and the body contacts. A flash coat will work for a while, but will wear away, making the contact problem worse. Body on the cheaper ones is only going to be tin plated, because silver is expensive, and tin plate is good enough to pass initial testing. Likely stamped out of a long roll of tin plated steel, and then used in a long strip to injection mould a load of switch bodies, then punched out and formed after assembly.
@@pahom2 Yes the gold plate on the PCB is good, but needs to be thicker than ENIG for a long lasting contact, needs to be the thickness used for edge connectors, as the ENIG coat is more there for keeping the exposed copper surface from corroding than as a wearing layer. Thin coat will wear off after a few thousand cycles exposing the bare nickel plate under it, and that in turn will wear away exposing the copper which will oxidise fast. If you want the most reliable contact cheap you will want a capacitive sensing pad under the PCB surface to sense distance from the dome, which will last till the PCB itself wears away. There are plenty of more expensive keyboards that did exactly this, or where they used hall effect sensors per key to detect a moving magnet. Not a cheap option though.
@ Generally well known brand names, and the higher end switch assemblies they supply. ALPS and Klixon come to mind, but there are a number of Aerospace suppliers of them that make them with gold alloy contacts that are rated for hundreds of millions of switch cycles. You pay for them though, as each comes with it's own serial number and test certificate.
Tin oxide is a tenacious insulator! As Apple learned with the Apple /// -- the memory board plugged into the motherboard with standard pins at each end. Engineers specified rhodium and gold for the pins and connectors. Purchasing went with tin on tin, which was cheaper. Oops. Thermal cycling, tin oxide, failing computers...
Any of you switch afficionados out there? Weeeeell don't mind if I do! 😉 When it comes to these tactile microswitches the difference between the cheapest of the cheap and the good quality "expensive" brands like ALPS is actually surprisingly low. Yes, they look a bit rougher around the edges, but if things like bouncing isn't a big issue for you they will perform just about the same. Even the cheapies last for a ridiculously long time, as you know from your look at snap domes in the past. I definitely think the failure of your switch was due to mechanical wear on the plating, which when worn through opened up for tarnishing with a less conductive oxide. I would contact an ALPS rep in Australia. They love sending out sample packs. They have these beautiful "catalog" boxes which open up with a beautiful display of many of their switches which you easily could just spend an entire wonderful afternoon flicking and clicking. They have a broad selection of snappy ones like these all the way to really nice soft touch long travel ones too. Truly a sight to behold!
Good timing, was about to open up switches in my pocket garage door opener. Some of the buttons shortened out, opening and closing the garage door when I'm not around and also draining the batteries on the unprogrammed buttons (this one took me a while to figure out). I thought it is dust from my woodworking, but corrosion makes more sense. I keep it in the pocket when working outside and it is easy for the sweat to get in.
i took apart one of these switches once when it failed on an old scooter charger the dome was totally etched through, the switch put 5v across a pulldown in to a 2.2u cap ... the pulldown was 4.7 ohms and passed an amp i assume someone at some point forgot to put in a 'k' in the schematic and it simply worked and no one caught it, but that poor 1/4w resistor and 7805 survived but for this i assume repeated pressing etched away a criminally thin plating of silver and let it oxidize
Bloody car keys are a nightmare for this!! Replaced mine after about 9 years of reliable service and after 6 months, the replacement goes bad!! Must have been one from the ShenZhen market at 5 on a Friday.
Huh, this is an unforseen benefit of my car key, I guess. I've pushed the button maybe 5 times in the past year (yay keyless, the one modern car feature I like).
One of my cars is too new for buttons to go bad (wireless fob that unlocks once I get close and press the button on the car) and the other one is too old. Guess I've managed to avoid these pesky buttons :P
I have done switch replacements on keys, thank you for the Chinese manufacturers who make the case copies that are close enough to work, and have the case parts, the seals and the rubber key moulds along with the switches and a key blank all in a cheap package. Cheaper than the OEM part by a lot, and you just replace the switches, transfer the board and battery along with the original key into the case and it works again.
Car keys of course can easily be much more prone to wear as they'd be outside, close to your salty and sweaty skin etc... Would definitely shorten the lifespan. Too bad Dave didn't test the stainless with a magnet, because that would probably do the job!
1:15 - 1:33 Oh, really? So THAT'S why some of my older equipment thinks i'm pressing buttons other than the one I'm actually pressing! I've wondered this for years, and never really figured out what could possibly be wrong! Huh...!
Ha.. I watched the entire video and it took until your comment to click with me.. I have a volume button on the steering wheel of a car that sometimes goes down when it is supposed to go up. I bet it's the same thing.
Thank you - I just run over that again and got it, genius, resistors for different voltages instead of a multiplexer, and if you won't go to the expense of a multiplexer then the switches will be cheap and the resistor network will go faulty too! Wow, I learnt today! :D
@@StreuPfeffer dave will be replacing them, because that is what building management expects. Tenants never get anything out of it other than maybe the gratitude of neighbors
Shhhhh it's by DESIGN no one knows what MTBF is these days - isn't it great ? Just like no one knows what a virus is, who made it or where it came from :-)
Very interesting! I'd bet that the CNK and the eBay cheapie are probably fairly close in performance - the dimple/split on the centre contact looks to be critical in avoiding a single point of contact (and thus a single point to corrode/wear) with the dome - but the eBay cheapie is probably in the same price range as the one from the aircon. Bargains to be had if you cut the right corners. I wonder if the CNK one was actually made air-tight, given that the top didn't pop off even when the lugs were cut...
This video was definitely very interesting. Who knew what was inside. As always, thanks for your fantastic and informative videos. I've watched so many I'm developing an Aussie accent.
Silver does corrode but the oxide itself is still conductive, that's why it is used for switch and relay contacts. In some of the machines we build at work we use coin silver for the contacts.
Thanks for the dive... I was going to suggest that you take the actuator from the bad switch and move it to a new one... melting the top down should be not too hard. Now I want to see the original switch fully repaired! Get some silver polish and a Q-tip and then treat it with Caig Labs magic liquid! Rotate the dome 90deg. I've done switch repair with vintage musical equipment, you can drill out rivets and use 2-56 hardware to bolt them back together.
I just finish fixing one 2 days ago and now this video pops up! Mine failed in the exact same way. As a temp fix while waiting for a replacement, I scratched off the oxide layer and the switch is working again (for now)
I have repaired and replaced various micro switches with and without micro controllers, unfortunately as a rule they are not made to be replaced. Good to see the effort though. Cheers from Canada.
In my Saitek X55-Rhino stick I had to replace some of them already within fife years of use. But in my case the mechanical tactile dome failed and lost it's springiness resulting in low tension to the four way switches in the upper part of the stick. Good luck I had several of theses switches in spare salvaged from an old VCR front panel. :)
as there is permanently some voltage between contacts , humidity even in Aussi , some poluants in the air , I would encline for corrosion by electrolysis between the different plated metals used...should happen to many of those units , best wishes for new year from France...
I have a Dual contact for the camera shutter. One to pre focus then 2nd to take the photo. My camera has a bad pre focus and a semi bad shutter. I was told to soak the top button in IPA. But if the switch is sealed like these, that will not help. After a few attempts it seem a little better but I need to open the camera for a real fix. There is no snap either so the dome may be flatten.
Ah, that is why my old Denon DVD player believes I'm pushing the hdmi type button when I'm actually pushing the eject button. I always thought that it had to do with a bad seated flex cable or even a broken flex cable. Thanks for this video!
I've cleaned hundreds of these with just a small wire brush, it usually gets 2~3 more years out of em. I've also never run across any of em that are really any better than the next, they all seem to be built pretty much the same. Also, please, MORE of this kinda stuff, loved it! Especially now with the enhanced extreme close up capabilities.
And the fact the switching mechanism is a metal dome snapping between different stable states is why contact cleaner doesn't do much for them, compared to what it will often do for things like pots. There's very little in the way of wiping action to allow the contact cleaner to get the surface corrosion to wipe off. I expect a major difference between different quality tactile switches is the metal used in the dome and contacts and how resistant to corrosion they are.
I think the dimple on the inner contact of the second switch is an attempt at having that contact self-scrub corrosion. The inner contact could rub a ring shaped area as the plunger forces the dome into the dimple. With how the dome moves as it deforms, the outer contacts can do the same thing on the nubs on those contacts. The third switch also looks like the center contact is a self-scrubbing design, but with two linear wear patches instead of a ring.
I had (have, actually) the same random failure on my crt tv. Swaped over all resistors years ago and since it didint fix the issue, I suspected it was the controllers fault. You gave me hope, those tact switches are cheap and easy to replace!
Is it a Thomson? It's a very common issue with them. You have to replace the switches *AND* wash off both sides of the board around the switches and the uCon thoroughly with 95+% IPA, the solder side twice, before and after installing the new switches.
@@mrnmrn1 Nope, a chinese tv with a samsung tube and a samsung clone chassis. Swapped out the switches, cleaned all flux and now it works wonderfully well. Too bad I couldn't find the more silent ones, but still happy I can use them again
We used to use lots of silver plated RF connectors for MRI electronics because nickel is magnetic. This type of corrosion is common for silver plating. Couldn't tell you what it is or how conductive it is. Suppliers now either produce gold-plated connectors or some proprietary plating for non-magnetic applications.
Interesting to see the corrosion, thanks for sharing. You can clearly see the ebay Dodgy Brothers version is made down to a price. The failed switch looks pretty much the same quality as the good one. If it averages one on and one off a day, say 14 actuations a week, 728 a year, you'd expect at least 10 years minimum life. Octopart datasheets show 100,000 actuations upwards (137 years!). How old was this one that failed?
This was exactly the problem with a JVC receiver. There was so much corrosion inside. Another video used deoxit and an engraver on the unopened plunger to rub the corrosion off it! I sliced off tabs and cleaned the guts with deoxit, which was only moderately successful.
that era of tact switches were very prone to failure. Contact cleaner would never really help; replacing the switch always did. Glad to finally see the failure inside. One would assume an issue with the material used for plating?
Fascinating - I've replaced dozens of these switches in LCD monitors and TVs but never bothered to open them up. Funny enough, while most failed high-resistance like yours, I did see one that failed shorted (30 ohms or so). I wonder what failure mode caused that!
I think that better tollerance on the face plate would be better for the life of the switch as well as it would limit scraping on the contacts as the switch was depressed. And it may also be better for dust ingress. I see the button on the CNK is also keyed so it won't turn like the switch from your controller, but unlike the second swich you tore down.
My 5 year old doorbell stopped working. After detective work discovered it to be the tactile switch. Cheap naff design but then looking them up, the whole push bell mechanism is £2.50 retail. They can't be using using quality parts at that price.
Those two side contacts seem as important as the center one, because the disc moves freely. On the faulty one, the plating is worst on the sides. Also, in C&K one, the center pin is cut in half to work kind of as dual contact? Could potentially double the cycles if there's some galvanic degradation on the contact point?
Actually, I like that One Hung Lo Ebay switch the best. I'm not sure, but I think that the dimple in the middle contact might be a part of a clever self-cleaning mechanism. As the contact disc flexes and makes the contact, the contact surface is elongating slightly, which means that it will rub ever so slightly on the contact when contacting and thus cleaning it. At the same time, the dimple will trap a tiny amount of air that will blow out via the contact surface as the dome slams onto the contact. Similarly, when released, the air will rush in and also create a movement of air across the contact surfaces. That would mean that it would rub it's contacts clean and blow off any debris off the contact surface.
So if there was a tiny bit of tolerance gap the dome could rotate slightly each time the switch is pressed, just randomly by the bounce back action, the wear could be spread over the entire disk.
I just took apart a Schurter Inc. 1301.9302 that I got from Digikey and it looks almost identical to the CNK switch (the one on the left at 13:38), except the split/slot in the contact is at a jaunty angle. Puzzling. Patent dodging? Who knows.
Use magnets to check for stainless steel it also has a slight gold tinge to it compared to nickel. Steel makes better springs than any other material. It doesn't matter what you plate steel with you're going to wear through the plating eventually where it hit the contacts and corrosion will soon follow.
Life expectancy depends on current and also switching frequency. There is sometimes also a separate rating for electrical and mechanical lifespan. The mechanical lifespan should be way higher than the electrical.
I replaced the same tact switches shown here in my 28-year-old digital setting circle computer on my telescope 3 months ago. I replaced these switches twice before. I did took two apart while my own Digi-Key order was being filled out and shipped as I had an observing session that night. Same thing. The gold tint is silver tarnish. I manage to clean using the wire brush pick tool. I got the computer working plus the lead-acid battery charger that was getting dodgy in its own menu switches. I got the order in and I replaced all of the tact switches in both units. A lot better operation in both units. Then i found 2 switches from the last order 12 years ago and found that they also had resistance values higher than the new switches. Even stored in a bag they will still tarnish.
Using a multiple resistor voltage divider can be made almost as reliable as a key matrix by using the switches to select where the ADC is connected to the resistor divider instead of having a fixed resistor and connecting another one in the circuit with the switch. This way the internal resistance of the switch would be negligible in relation to the ADC's internal resistance.
So, what you are saying in the video, thers no solution for the tactail switch? Unless if we change ut with the same exact part?, we cant repair it or smooth it or polished the the silver plate
Its probably too late but you could show us how contact cleaner would work on this AC one. That would give us an idea if dousing such switch with contact cleaner is decent solution in case if such switch is unavailable at the moment or not.
I had to replace a tiny power switch like that in a co-worker's external hard drive. I used a replacement switch from some old electronic device. He was worried that he would lose all of his data and was so happy that it was a simple fix. The switch I had was a very high resistance, nearly open. I took it apart but didn't see an obvious problem like corrosion, so I'm not sure what happened to it.
This kind of switch is highly susceptible to wash water ingress after assembly. This makes it likely that a sample solution of all the nasty stuff the washer is trying to wash off the rest of the assembly ends up inside the switch. As time passes, water evaporates and the solution concentrates and leads to corrosion. The best way to use these switches is to hand solder with no wash flux solder after the board has gone through auto assembly and wash process. More reliable buttons that lend themselves to volume production are membrane and or silicone button arrays, or capacitive touch buttons.
IIRC, pure stainless steel is non-ferrous. You might be able to test with a magnet, bearing in mind the plating can skew the results. Maybe a weak magnet to reduce false positives? 😁
@@clemensruis Yes, but I'm not sure if it also ensures sufficient self cleaning effect. Also, the large contact surface will not make contact all at once, which can cause increased bouncing.
In my experience, especially those with silver contacty, a good soak in the right chemicals can make them fresh again, but the better they are, the more hermetically they are sealed so its not only hard to get that cleaner in, its also hard to get it out. There have been desperate times where a tiny vacuum chamber (aka syringe) was a useful tool
Really interesting video, thanks! I've been looking at mechanical keyboards and switches lately. I'm playing with the idea of building my own DIY gaming keypad, or split curved keyboard. But now I'm looking at things like the wooting two HE which uses really awesome stuff like all analog keys using hall effect sensors haha
Although it will be best to replace, cleaning actually does work quiet well. I have cleaned more than a few of those switches and none of them failed 2nd time. However, I don't just spray contact cleaner from outside. I actually take it apart and clean contact points. The issue usually is oxidation on silver plating. You can glue lid back on with very small drop of super glue.
But let me ask this as question. Is it really worth that work ? I mean you think of your work as job with payment. Even if you only need 2 minutes for opening cleaning and closing. Is your loan low enough to beat a cheap switch for a few cent's 😂 ?
@@sebastianschmidt566 Well, these cheap switches aren't cheap if you don't have them on hand and you have to fix right at the moment. If you repair electronics for living, yes you should keep bunch of different switches in stock. If you are just trying to fix your or friend's electronics, is it worth it to order a switch for few cents then pay $10 for shipping and wait a week ?
2:07 I was almost screaming to the screen during the whole video to show the underside of the original switch. I bet it's an Omron. Not exactly a dodgy one-hung-low brand.
@@EEVblog Thanks! Interesting, this brown shaft is their 'trademark'. I don't have an Omron made one handy, but IIRC, they have OMRON moulded into their bottom. I'll check it in january, we have some at work. My 'new' Technics tape deck just arrived yesterday. The stop button sometimes rewinds, sometimes plays, the rarest thing it does is its intended function... All the boards are flooded with oil, I guess (judging by the smell) someone sprayed half a can of WD40 into this poor thing... He washed off the grease from all the pot shafts with it, they are all rotating completely freely, without any resistance. I am not happy right now, it was almost $70 :-( .
@@mrnmrn1 Ai, but contact spray can do the same, wash all of the grease (and with that the 'feel') out of the shaft, and leave it on the tracks, effectively making them dirtier than before. If possible, i'll take pots apart rather than blindly spit in them.
@@erikdenhouter Exactly! That's what I always do, too. I use contact cleaner, but on a Q-tip, to wipe the resistve track and moving contacts with it. After that, I apply a generously thick layer of silicone grease to the track. It both protects the track from wearing out by its lubricant effect, and protects the silver plated contacts from suphidation by sealing them from the atmosphere. I do the same with rotary encoders. The first time I've done this was almost 20 years ago, and that same rotary encoder is still working fine, although it failed within 5 years with its factory condition (with dry contacts, they were all black when I disassembled it).
what year you are in Dave? that still use tactile switches for AC controller. we now use rubber carbon. cleaning that corrosion / carbon deposit with sand paper or a mini file can fix that, i've done on a few, for not so long period though as the original 1st performance, so replacing it altogether can be a wise move. ymmv.
At 13:17 you can see it is one piece of metal, just the shading made it look like 2 before. Every now and then I have to change the my wacom mouse buttons.
Switch repair as follows. Disassemble with flush cutters to leave as much plastic as possible. Polish all switch surfaces with fiberglass pen. Wash all fiberglass particles away taking care not to embed them in yourself. Add a few drops of pure Deoxit. Reassemble by melting protruding plastic pins with soldering iron tip. Due to the fact that there are so many different styles of these switches with varying button heights I've had to rework hundreds of these things. Spraying cleaner into these switches will get you nowhere.
@Tone. Great point and you are absolutely right. I had to do the rebuilds because the company I worked for did a 10X mark-up of parts. So forty bad switches would cost more than customer would pay. I had my choice to make a little or nothing at all.
The Best of the three switches is the "cheap eBay" one. The other two have silver plating, the oxidation of which, is the cause of your "dodgy" switch. The two ways to get long life from silver low current contacts are hermetic sealing or oxygen barrier, i.e. silicone, or other, grease. Silver plated switches that actually switch some current, typically 500 mA or more, self clean with a small "arc" which cleans of any oxidation until eventually the silver wears away and the base metal gets corroded.
Isn't that called 'wetting current'? I had an old (much heavier duty) pushbutton which wasn't giving good resistance readings on the multimeter. I used it to switch around an amp and then it worked. Same idea, I guess.
havnt watched the entire video so i dont know if you FULLY disassemble it to the bare board 50% through the video but the pad on the outside is shaped like a omega symbol ---("'')--- and the center pin is kinda the same but goes into the center instead of around the sides ---()--- so 2 pads go to each edit: replaced _ with --- as youtube modifies the comment and treats them like operators
Samsung TVs from around 2010 have the same problem with the buttons on the TV. Volume goes up or down, channels change, etc. They fail in open position! I once opened one up and only found a tiny trace of some material that bridged the central contact with the outer contact. No signs of corrosion or wear on any part since those buttons never get used. Very strange. It's good that Aliexpress has large kits of buttons of all shapes :) They are all crap, anyway.
Nice Video Dave Instead of changing the whole console for its malfunctioning we could change the button and save the world but we need to know some information about the design
Basics! This is basics, if you reach the people who want to learn Learning these new interesting things is never boring! "Surgery? What surgery? I did understand autopsy!?" The doctor said
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If both contacts are made of the same material corrosion should be minimal. The less corrosive the top coating of the contacts is, you should have less corrosion (silver, golf). It all depends on the environment where the switch is used.
By any chance would you know whether your Targano Microscope uses a 14-bit micro? The zoom level went upto 4000xH. If so why would they do that? Using a 14-bit micro instead of 16? Edit: Corrected grammar
Ha ha. I was one of the "mutterers" and I duly watched this follow-up, even after being touche'd by Dave on the original ☺️. Do miss the more involved teardowns tho.
My GF just picked up the phrase, and I quote: @ 09:09 ; "Go down the shaft and squirt the whole thing". Well, than try to explain you are just watching a technical video by an aussie tearing down a button. PS. She was really impressed with the @ 05:18 30 cm working distance.
Looks just like the contact disk on a GM Delco-Remy starter motor solenoid. They would develop carbon deposits and be intermittent. We would take the plastic end cap off the solenoid and rotate the disk 180 deg. to a nice fresh spot and it would be good to go for anothert 50,000 miles. PS @9:25 The contact disk I mentioned was just plain old copper, but the black carbon deposits had the exact same color and look The carbon would come from the tiny spark it made when contacting and releasing. It "welded" a tiny nub of carbon released from the miniscule molten metal itself. Over time it built up from thousands and thousands..millions? of times the key was turned.
The side patches would definitely be the issue there I'd say. Man, totally blackened. No matter how hard you press on the center, it's not making better contact on those sides as they are "sprung". If you were to spin the disk a few degrees putting the blackened parts out of contact area, it'd work for a while maybe.
Likely source of the problem (if indeed it is silver plated): air pollution. Silver is no longer good for electrical contacts. Gold is the way to go. Silver sulphide is actually a semiconductor. See also: www.iaras.org/iaras/filedownloads/ijch/2018/017-0001(2018).pdf
Hey everyone, i'm wondering about the maximum current rating for those short circuit common terminals, I often used this "component jumper" as a trick in pcb tracing to replace jumper wire, all I can find in the datasheet is the small current rating (about 50 mA) probably the current rating of the dome which explains the low value. Has anybody ever came across these specs? or the dome rating is actually the same as this short circuit rating?
Haha this is epic level trolling.
"Mutter mutter 15 minutes fixing a dodgy switch mutter mutter"
"Really, here's 15 more minutes of me taking that switch apart... enjoy!"
@@Okurka. i forgot to add one to my Xmas list 😂
dave gives what the people ask for
MUTTER!
Mutter is a german word which means mother or mum or nut!
@@DavidKrautscheid It also means to grumble. At least it does in swedish.
This was way more interesting than I may have thought. Thanks
Taking everything to bits is always interesting, especially if you have a nice microscope like the TaGaRno!
@@rkan2 Tagano
@@EEVblog fiXed
@@EEVblog Tagarno
@@sylvainlazare1114 LOL, yeah Tagarno
Silver oxide is reasonably conductive, the black is silver sulphide, which is an insulator, or at least a poor resistor with 5V applied. Silver plated with a thin coat on the one side of brass sheet before being punched out and into the die to shape it. The more expensive uses stiffer and harder nickel, which is more resistant to corroding, and can get by in regular atmosphere with no coating on it, but yes for the best you want heavy gold plating on the disk and the body contacts. A flash coat will work for a while, but will wear away, making the contact problem worse.
Body on the cheaper ones is only going to be tin plated, because silver is expensive, and tin plate is good enough to pass initial testing. Likely stamped out of a long roll of tin plated steel, and then used in a long strip to injection mould a load of switch bodies, then punched out and formed after assembly.
What about the domes over PCB mounting. Would a gold plated PCB pad under the dome make an equally reliable contact?
@@pahom2 Yes the gold plate on the PCB is good, but needs to be thicker than ENIG for a long lasting contact, needs to be the thickness used for edge connectors, as the ENIG coat is more there for keeping the exposed copper surface from corroding than as a wearing layer. Thin coat will wear off after a few thousand cycles exposing the bare nickel plate under it, and that in turn will wear away exposing the copper which will oxidise fast.
If you want the most reliable contact cheap you will want a capacitive sensing pad under the PCB surface to sense distance from the dome, which will last till the PCB itself wears away. There are plenty of more expensive keyboards that did exactly this, or where they used hall effect sensors per key to detect a moving magnet. Not a cheap option though.
@ Generally well known brand names, and the higher end switch assemblies they supply. ALPS and Klixon come to mind, but there are a number of Aerospace suppliers of them that make them with gold alloy contacts that are rated for hundreds of millions of switch cycles. You pay for them though, as each comes with it's own serial number and test certificate.
Tin oxide is a tenacious insulator! As Apple learned with the Apple /// -- the memory board plugged into the motherboard with standard pins at each end. Engineers specified rhodium and gold for the pins and connectors. Purchasing went with tin on tin, which was cheaper. Oops. Thermal cycling, tin oxide, failing computers...
Any of you switch afficionados out there? Weeeeell don't mind if I do! 😉
When it comes to these tactile microswitches the difference between the cheapest of the cheap and the good quality "expensive" brands like ALPS is actually surprisingly low. Yes, they look a bit rougher around the edges, but if things like bouncing isn't a big issue for you they will perform just about the same. Even the cheapies last for a ridiculously long time, as you know from your look at snap domes in the past. I definitely think the failure of your switch was due to mechanical wear on the plating, which when worn through opened up for tarnishing with a less conductive oxide.
I would contact an ALPS rep in Australia. They love sending out sample packs. They have these beautiful "catalog" boxes which open up with a beautiful display of many of their switches which you easily could just spend an entire wonderful afternoon flicking and clicking. They have a broad selection of snappy ones like these all the way to really nice soft touch long travel ones too. Truly a sight to behold!
Bet the reps will send one in to the next mailbag, not only from ALPS but every other switch manufacturer. Dave will be swimming in switch parts.
@@SeanBZA No doubt
Now this is the random EEVBlog stuff I subscribed for 😅
Soo good to see this video after reading the comments on the last video! Love your responsiveness to comments dave
Good timing, was about to open up switches in my pocket garage door opener. Some of the buttons shortened out, opening and closing the garage door when I'm not around and also draining the batteries on the unprogrammed buttons (this one took me a while to figure out). I thought it is dust from my woodworking, but corrosion makes more sense. I keep it in the pocket when working outside and it is easy for the sweat to get in.
i took apart one of these switches once when it failed on an old scooter charger
the dome was totally etched through, the switch put 5v across a pulldown in to a 2.2u cap ... the pulldown was 4.7 ohms and passed an amp
i assume someone at some point forgot to put in a 'k' in the schematic and it simply worked and no one caught it, but that poor 1/4w resistor and 7805 survived
but for this i assume repeated pressing etched away a criminally thin plating of silver and let it oxidize
Bloody car keys are a nightmare for this!! Replaced mine after about 9 years of reliable service and after 6 months, the replacement goes bad!! Must have been one from the ShenZhen market at 5 on a Friday.
Huh, this is an unforseen benefit of my car key, I guess. I've pushed the button maybe 5 times in the past year (yay keyless, the one modern car feature I like).
One of my cars is too new for buttons to go bad (wireless fob that unlocks once I get close and press the button on the car) and the other one is too old. Guess I've managed to avoid these pesky buttons :P
@Dusty 99 Both cars are broken junkyard pulls, I'm not rich lol
I have done switch replacements on keys, thank you for the Chinese manufacturers who make the case copies that are close enough to work, and have the case parts, the seals and the rubber key moulds along with the switches and a key blank all in a cheap package. Cheaper than the OEM part by a lot, and you just replace the switches, transfer the board and battery along with the original key into the case and it works again.
Car keys of course can easily be much more prone to wear as they'd be outside, close to your salty and sweaty skin etc... Would definitely shorten the lifespan. Too bad Dave didn't test the stainless with a magnet, because that would probably do the job!
Thank you for making this video. It helped me to repair a part instead of calling a technician and replacing it. And I saved around 150-200 euros.
1:15 - 1:33 Oh, really? So THAT'S why some of my older equipment thinks i'm pressing buttons other than the one I'm actually pressing! I've wondered this for years, and never really figured out what could possibly be wrong!
Huh...!
Ha.. I watched the entire video and it took until your comment to click with me..
I have a volume button on the steering wheel of a car that sometimes goes down when it is supposed to go up. I bet it's the same thing.
Thank you - I just run over that again and got it, genius, resistors for different voltages instead of a multiplexer, and if you won't go to the expense of a multiplexer then the switches will be cheap and the resistor network will go faulty too! Wow, I learnt today! :D
Now you really should be speaking with building management - there are probably dozens of those aircon controllers experiencing the same issue.
Dave will be replacing them for 5%-10% rent decrease for the next 10 years. Maybe :D
@@StreuPfeffer dave will be replacing them, because that is what building management expects. Tenants never get anything out of it other than maybe the gratitude of neighbors
Shhhhh it's by DESIGN no one knows what MTBF is these days - isn't it great ? Just like no one knows what a virus is, who made it or where it came from :-)
Happy new year from the azores, Portugal! Really like your videos!
Really good picture from that Tagarno microscope! The depth of field isn't too bad either.
@@CliveChamberlain946 Yes, I still use my Mantis for any actual work I'm not recording. But sadly it's got the most attrocious camera ever.
Very interesting! I'd bet that the CNK and the eBay cheapie are probably fairly close in performance - the dimple/split on the centre contact looks to be critical in avoiding a single point of contact (and thus a single point to corrode/wear) with the dome - but the eBay cheapie is probably in the same price range as the one from the aircon. Bargains to be had if you cut the right corners.
I wonder if the CNK one was actually made air-tight, given that the top didn't pop off even when the lugs were cut...
This video was definitely very interesting. Who knew what was inside. As always, thanks for your fantastic and informative videos. I've watched so many I'm developing an Aussie accent.
Awesome follow up.
I reckon the dark patches on the edges of the dome caused most of the trouble.
Thanks for sharing. 😉👌🏼
Silver does corrode but the oxide itself is still conductive, that's why it is used for switch and relay contacts. In some of the machines we build at work we use coin silver for the contacts.
Thanks for the dive... I was going to suggest that you take the actuator from the bad switch and move it to a new one... melting the top down should be not too hard. Now I want to see the original switch fully repaired! Get some silver polish and a Q-tip and then treat it with Caig Labs magic liquid! Rotate the dome 90deg. I've done switch repair with vintage musical equipment, you can drill out rivets and use 2-56 hardware to bolt them back together.
Silver does oxcidise but silver oxcide is still very conductive.
Great video - I must get around to fixing a mate's synth with dead keys!
I just finish fixing one 2 days ago and now this video pops up!
Mine failed in the exact same way.
As a temp fix while waiting for a replacement, I scratched off the oxide layer and the switch is working again (for now)
I have repaired and replaced various micro switches with and without micro controllers, unfortunately as a rule they are not made to be replaced. Good to see the effort though. Cheers from Canada.
In my Saitek X55-Rhino stick I had to replace some of them already within fife years of use. But in my case the mechanical tactile dome failed and lost it's springiness resulting in low tension to the four way switches in the upper part of the stick. Good luck I had several of theses switches in spare salvaged from an old VCR front panel. :)
Why do I feel this was just made to troll the haters on the previous vid? I'm still gonna enjoy it :D
It was a good video anyway ^^
@@Irilia_neko A win-win.
I've always been curious of those cheap switches. They always seem to be the first thing to fail.
as there is permanently some voltage between contacts , humidity even in Aussi , some poluants in the air , I would encline for corrosion by electrolysis between the different plated metals used...should happen to many of those units , best wishes for new year from France...
I have a Dual contact for the camera shutter. One to pre focus then 2nd to take the photo. My camera has a bad pre focus and a semi bad shutter. I was told to soak the top button in IPA. But if the switch is sealed like these, that will not help. After a few attempts it seem a little better but I need to open the camera for a real fix. There is no snap either so the dome may be flatten.
Ah, that is why my old Denon DVD player believes I'm pushing the hdmi type button when I'm actually pushing the eject button. I always thought that it had to do with a bad seated flex cable or even a broken flex cable. Thanks for this video!
I've cleaned hundreds of these with just a small wire brush, it usually gets 2~3 more years out of em. I've also never run across any of em that are really any better than the next, they all seem to be built pretty much the same. Also, please, MORE of this kinda stuff, loved it! Especially now with the enhanced extreme close up capabilities.
Do you clean them without taking them apart?
@@Spitflies no point in that is there?
@@eshep well how do you reseal them then?
@@Spitflies cyanoacrylate around the u-joint, same as you commonly find em usually is enough. You can always RTV over that if you need watertightness.
Great vid, Dave. BTW, those switches are CKN. Happy New Year.
Happy New Year to you and the family Dave!
And the fact the switching mechanism is a metal dome snapping between different stable states is why contact cleaner doesn't do much for them, compared to what it will often do for things like pots. There's very little in the way of wiping action to allow the contact cleaner to get the surface corrosion to wipe off.
I expect a major difference between different quality tactile switches is the metal used in the dome and contacts and how resistant to corrosion they are.
I think the dimple on the inner contact of the second switch is an attempt at having that contact self-scrub corrosion. The inner contact could rub a ring shaped area as the plunger forces the dome into the dimple. With how the dome moves as it deforms, the outer contacts can do the same thing on the nubs on those contacts. The third switch also looks like the center contact is a self-scrubbing design, but with two linear wear patches instead of a ring.
I had (have, actually) the same random failure on my crt tv. Swaped over all resistors years ago and since it didint fix the issue, I suspected it was the controllers fault. You gave me hope, those tact switches are cheap and easy to replace!
Is it a Thomson? It's a very common issue with them. You have to replace the switches *AND* wash off both sides of the board around the switches and the uCon thoroughly with 95+% IPA, the solder side twice, before and after installing the new switches.
@@mrnmrn1 Nope, a chinese tv with a samsung tube and a samsung clone chassis. Swapped out the switches, cleaned all flux and now it works wonderfully well. Too bad I couldn't find the more silent ones, but still happy I can use them again
We used to use lots of silver plated RF connectors for MRI electronics because nickel is magnetic. This type of corrosion is common for silver plating. Couldn't tell you what it is or how conductive it is. Suppliers now either produce gold-plated connectors or some proprietary plating for non-magnetic applications.
Interesting to see the corrosion, thanks for sharing. You can clearly see the ebay Dodgy Brothers version is made down to a price. The failed switch looks pretty much the same quality as the good one. If it averages one on and one off a day, say 14 actuations a week, 728 a year, you'd expect at least 10 years minimum life. Octopart datasheets show 100,000 actuations upwards (137 years!). How old was this one that failed?
It's a plastic dust compacted and stuck to the bottom of the dome. Heat it up - it should show itself right away.
This was exactly the problem with a JVC receiver. There was so much corrosion inside. Another video used deoxit and an engraver on the unopened plunger to rub the corrosion off it! I sliced off tabs and cleaned the guts with deoxit, which was only moderately successful.
that era of tact switches were very prone to failure. Contact cleaner would never really help; replacing the switch always did. Glad to finally see the failure inside. One would assume an issue with the material used for plating?
This video pushed all the right buttons.
Fascinating - I've replaced dozens of these switches in LCD monitors and TVs but never bothered to open them up.
Funny enough, while most failed high-resistance like yours, I did see one that failed shorted (30 ohms or so). I wonder what failure mode caused that!
a ruptured disc, time to see the chiropractor.
@@TuttleScott I was thinking tin whiskers or other growth but a herniated disc sounds very plausible indeed.
Measure the resistance between the corroded spot?
I think that better tollerance on the face plate would be better for the life of the switch as well as it would limit scraping on the contacts as the switch was depressed. And it may also be better for dust ingress. I see the button on the CNK is also keyed so it won't turn like the switch from your controller, but unlike the second swich you tore down.
My 5 year old doorbell stopped working. After detective work discovered it to be the tactile switch. Cheap naff design but then looking them up, the whole push bell mechanism is £2.50 retail. They can't be using using quality parts at that price.
Those two side contacts seem as important as the center one, because the disc moves freely. On the faulty one, the plating is worst on the sides.
Also, in C&K one, the center pin is cut in half to work kind of as dual contact? Could potentially double the cycles if there's some galvanic degradation on the contact point?
So the common failure mode is galvanic corrosion on the tactile dome, because the silver plating is soft and thin wore through?
Actually, I like that One Hung Lo Ebay switch the best. I'm not sure, but I think that the dimple in the middle contact might be a part of a clever self-cleaning mechanism. As the contact disc flexes and makes the contact, the contact surface is elongating slightly, which means that it will rub ever so slightly on the contact when contacting and thus cleaning it. At the same time, the dimple will trap a tiny amount of air that will blow out via the contact surface as the dome slams onto the contact. Similarly, when released, the air will rush in and also create a movement of air across the contact surfaces. That would mean that it would rub it's contacts clean and blow off any debris off the contact surface.
Maybe some of that CAIG Laboratories DeoxIT would help it. It was always around in the repair depot around here.
So if there was a tiny bit of tolerance gap the dome could rotate slightly each time the switch is pressed, just randomly by the bounce back action, the wear could be spread over the entire disk.
I just took apart a Schurter Inc. 1301.9302 that I got from Digikey and it looks almost identical to the CNK switch (the one on the left at 13:38), except the split/slot in the contact is at a jaunty angle. Puzzling. Patent dodging? Who knows.
Use magnets to check for stainless steel it also has a slight gold tinge to it compared to nickel. Steel makes better springs than any other material. It doesn't matter what you plate steel with you're going to wear through the plating eventually where it hit the contacts and corrosion will soon follow.
There is also magnetic stainless steel, the magnet test is not always perfect.
@@HeyBirt Thanks, that's what I wanted to comment. :) Also this magnet test is not positive with brass.
That camera is absolutely fantastic holy shit.
Life expectancy depends on current and also switching frequency. There is sometimes also a separate rating for electrical and mechanical lifespan. The mechanical lifespan should be way higher than the electrical.
Nickel plate is better than silver. If you want to know if something is plated, scratch it and see if you can scratch through to a base metal.
I replaced the same tact switches shown here in my 28-year-old digital setting circle computer on my telescope 3 months ago. I replaced these switches twice before. I did took two apart while my own Digi-Key order was being filled out and shipped as I had an observing session that night. Same thing. The gold tint is silver tarnish. I manage to clean using the wire brush pick tool. I got the computer working plus the lead-acid battery charger that was getting dodgy in its own menu switches. I got the order in and I replaced all of the tact switches in both units. A lot better operation in both units. Then i found 2 switches from the last order 12 years ago and found that they also had resistance values higher than the new switches. Even stored in a bag they will still tarnish.
Using a multiple resistor voltage divider can be made almost as reliable as a key matrix by using the switches to select where the ADC is connected to the resistor divider instead of having a fixed resistor and connecting another one in the circuit with the switch. This way the internal resistance of the switch would be negligible in relation to the ADC's internal resistance.
это все хорошо, но эти кнопки еще бывают с большими нестабильными утечками
So, what you are saying in the video, thers no solution for the tactail switch? Unless if we change ut with the same exact part?, we cant repair it or smooth it or polished the the silver plate
Its probably too late but you could show us how contact cleaner would work on this AC one.
That would give us an idea if dousing such switch with contact cleaner is decent solution in case if such switch is unavailable at the moment or not.
Is it just me or does the package for the "CNK" say "CKN"
I have also failed several those switches over time. Why they don't use corrosion free materials like nickel, stainless or smth?
I had to replace a tiny power switch like that in a co-worker's external hard drive. I used a replacement switch from some old electronic device. He was worried that he would lose all of his data and was so happy that it was a simple fix. The switch I had was a very high resistance, nearly open. I took it apart but didn't see an obvious problem like corrosion, so I'm not sure what happened to it.
This kind of switch is highly susceptible to wash water ingress after assembly. This makes it likely that a sample solution of all the nasty stuff the washer is trying to wash off the rest of the assembly ends up inside the switch. As time passes, water evaporates and the solution concentrates and leads to corrosion. The best way to use these switches is to hand solder with no wash flux solder after the board has gone through auto assembly and wash process. More reliable buttons that lend themselves to volume production are membrane and or silicone button arrays, or capacitive touch buttons.
IIRC, pure stainless steel is non-ferrous. You might be able to test with a magnet, bearing in mind the plating can skew the results. Maybe a weak magnet to reduce false positives? 😁
I'm no expert, but it looks like ultra thin plating on a poorly prepared surface. Was there ANY loose material in there?
is it just an illusion or does the center contact of the first one have tiny spikes to penetrate slight corrosion layers?
Yes, it is knurled for self cleaning. That's probably an Omron switch judging by the brown shaft.
@@mrnmrn1 I found the switch afficionado!
I'm actually impressed by the ebay switch. The dimple ensures a large contact surface.
@@clemensruis Yes, but I'm not sure if it also ensures sufficient self cleaning effect. Also, the large contact surface will not make contact all at once, which can cause increased bouncing.
In my experience, especially those with silver contacty, a good soak in the right chemicals can make them fresh again, but the better they are, the more hermetically they are sealed so its not only hard to get that cleaner in, its also hard to get it out. There have been desperate times where a tiny vacuum chamber (aka syringe) was a useful tool
Really interesting video, thanks! I've been looking at mechanical keyboards and switches lately. I'm playing with the idea of building my own DIY gaming keypad, or split curved keyboard.
But now I'm looking at things like the wooting two HE which uses really awesome stuff like all analog keys using hall effect sensors haha
My Roland D-50 needs several of those small suckers exchanged.
Although it will be best to replace, cleaning actually does work quiet well. I have cleaned more than a few of those switches and none of them failed 2nd time. However, I don't just spray contact cleaner from outside. I actually take it apart and clean contact points. The issue usually is oxidation on silver plating. You can glue lid back on with very small drop of super glue.
But let me ask this as question.
Is it really worth that work ? I mean you think of your work as job with payment.
Even if you only need 2 minutes for opening cleaning and closing. Is your loan low enough to beat a cheap switch for a few cent's 😂 ?
@@sebastianschmidt566 Well, these cheap switches aren't cheap if you don't have them on hand and you have to fix right at the moment. If you repair electronics for living, yes you should keep bunch of different switches in stock. If you are just trying to fix your or friend's electronics, is it worth it to order a switch for few cents then pay $10 for shipping and wait a week ?
I like how you switched it up with this video.. 😏
Even expensive high quality switches fail.
I had many Grayhill matrix keypads fail sending multiple digits when pressed.
2:07 I was almost screaming to the screen during the whole video to show the underside of the original switch. I bet it's an Omron. Not exactly a dodgy one-hung-low brand.
Just says "DIP E."
@@EEVblog Thanks! Interesting, this brown shaft is their 'trademark'. I don't have an Omron made one handy, but IIRC, they have OMRON moulded into their bottom. I'll check it in january, we have some at work.
My 'new' Technics tape deck just arrived yesterday. The stop button sometimes rewinds, sometimes plays, the rarest thing it does is its intended function... All the boards are flooded with oil, I guess (judging by the smell) someone sprayed half a can of WD40 into this poor thing... He washed off the grease from all the pot shafts with it, they are all rotating completely freely, without any resistance. I am not happy right now, it was almost $70 :-( .
@@EEVblog a quick google says TL1105 Series Tact Switches | E-Switch.com is a good possibility
@@mrnmrn1 Ai, but contact spray can do the same, wash all of the grease (and with that the 'feel') out of the shaft, and leave it on the tracks, effectively making them dirtier than before. If possible, i'll take pots apart rather than blindly spit in them.
@@erikdenhouter Exactly! That's what I always do, too. I use contact cleaner, but on a Q-tip, to wipe the resistve track and moving contacts with it. After that, I apply a generously thick layer of silicone grease to the track. It both protects the track from wearing out by its lubricant effect, and protects the silver plated contacts from suphidation by sealing them from the atmosphere. I do the same with rotary encoders. The first time I've done this was almost 20 years ago, and that same rotary encoder is still working fine, although it failed within 5 years with its factory condition (with dry contacts, they were all black when I disassembled it).
really enjoyed this
Yeah, especially nice to see with yhe Takano, really nice quality shots.
what year you are in Dave? that still use tactile switches for AC controller. we now use rubber carbon. cleaning that corrosion / carbon deposit with sand paper or a mini file can fix that, i've done on a few, for not so long period though as the original 1st performance, so replacing it altogether can be a wise move. ymmv.
At 13:17 you can see it is one piece of metal, just the shading made it look like 2 before. Every now and then I have to change the my wacom mouse buttons.
Switch repair as follows. Disassemble with flush cutters to leave as much plastic as possible. Polish all switch surfaces with fiberglass pen. Wash all fiberglass particles away taking care not to embed them in yourself. Add a few drops of pure Deoxit. Reassemble by melting protruding plastic pins with soldering iron tip. Due to the fact that there are so many different styles of these switches with varying button heights I've had to rework hundreds of these things. Spraying cleaner into these switches will get you nowhere.
@Tone. Great point and you are absolutely right. I had to do the rebuilds because the company I worked for did a 10X mark-up of parts. So forty bad switches would cost more than customer would pay. I had my choice to make a little or nothing at all.
Potentiometer teardown please dave
Nice video , can you switch the osd zoom from hex to decimal .
The Best of the three switches is the "cheap eBay" one. The other two have silver plating, the oxidation of which, is the cause of your "dodgy" switch. The two ways to get long life from silver low current contacts are hermetic sealing or oxygen barrier, i.e. silicone, or other, grease. Silver plated switches that actually switch some current, typically 500 mA or more, self clean with a small "arc" which cleans of any oxidation until eventually the silver wears away and the base metal gets corroded.
Isn't that called 'wetting current'? I had an old (much heavier duty) pushbutton which wasn't giving good resistance readings on the multimeter. I used it to switch around an amp and then it worked. Same idea, I guess.
havnt watched the entire video so i dont know if you FULLY disassemble it to the bare board 50% through the video but the pad on the outside is shaped like a omega symbol ---("'')--- and the center pin is kinda the same but goes into the center instead of around the sides ---()--- so 2 pads go to each edit: replaced _ with --- as youtube modifies the comment and treats them like operators
DeOxit can do amazing stuff to corroded contacts, but yeah, if you're in there anyway and have a replacement, why take the chance
Samsung TVs from around 2010 have the same problem with the buttons on the TV. Volume goes up or down, channels change, etc. They fail in open position! I once opened one up and only found a tiny trace of some material that bridged the central contact with the outer contact. No signs of corrosion or wear on any part since those buttons never get used. Very strange. It's good that Aliexpress has large kits of buttons of all shapes :) They are all crap, anyway.
Nice Video Dave
Instead of changing the whole console for its malfunctioning we could change the button and save the world but we need to know some information about the design
what is going to be next copper wires or screws ?
Basics! This is basics, if you reach the people who want to learn
Learning these new interesting things is never boring!
"Surgery? What surgery? I did understand autopsy!?" The doctor said
If both contacts are made of the same material corrosion should be minimal. The less corrosive the top coating of the contacts is, you should have less corrosion (silver, golf). It all depends on the environment where the switch is used.
Is the corrosion the same thing as “silver mica disease” in tube radio IF transformer capacitors?
Thank you!
I remember I had once found a computer keyboard that used one of these for every switch. Pretty cool considering how damn rare that apparently is.
By any chance would you know whether your Targano Microscope uses a 14-bit micro? The zoom level went upto 4000xH. If so why would they do that? Using a 14-bit micro instead of 16?
Edit: Corrected grammar
Dont know, it's never made sense to me.
Maybe it has a 14-bit ADC.
@@eDoc2020 Yup. Later that's what I thought might be case
Ha ha. I was one of the "mutterers" and I duly watched this follow-up, even after being touche'd by Dave on the original ☺️. Do miss the more involved teardowns tho.
"It's probably easier just to go down the shaft really and then squirt the whole thing" - Dave Jones, 2020
My GF just picked up the phrase, and I quote: @ 09:09 ; "Go down the shaft and squirt the whole thing".
Well, than try to explain you are just watching a technical video by an aussie tearing down a button.
PS. She was really impressed with the @ 05:18 30 cm working distance.
I wonder if they didn’t do the matrix cause they ran out of memory on the micro?
Looks just like the contact disk on a GM Delco-Remy starter motor solenoid. They would develop carbon deposits and be intermittent. We would take the plastic end cap off the solenoid and rotate the disk 180 deg. to a nice fresh spot and it would be good to go for anothert 50,000 miles.
PS @9:25 The contact disk I mentioned was just plain old copper, but the black carbon deposits had the exact same color and look The carbon would come from the tiny spark it made when contacting and releasing. It "welded" a tiny nub of carbon released from the miniscule molten metal itself. Over time it built up from thousands and thousands..millions? of times the key was turned.
The side patches would definitely be the issue there I'd say. Man, totally blackened. No matter how hard you press on the center, it's not making better contact on those sides as they are "sprung". If you were to spin the disk a few degrees putting the blackened parts out of contact area, it'd work for a while maybe.
Can you please be so kind a tell me what brand is the camera you are using for as a microscope... thx a million
Likely source of the problem (if indeed it is silver plated): air pollution. Silver is no longer good for electrical contacts. Gold is the way to go. Silver sulphide is actually a semiconductor. See also: www.iaras.org/iaras/filedownloads/ijch/2018/017-0001(2018).pdf
Hey everyone, i'm wondering about the maximum current rating for those short circuit common terminals, I often used this "component jumper" as a trick in pcb tracing to replace jumper wire, all I can find in the datasheet is the small current rating (about 50 mA) probably the current rating of the dome which explains the low value. Has anybody ever came across these specs? or the dome rating is actually the same as this short circuit rating?
What's the brand of your camera ....... thx
the fact that the corrosion was only on the contacts between 2 different metals points to some electrochemical corrosion.