Caig CaiKote44 for keyboard contacts

[chipaudette]

Hi Guys,

I was wondering if anyone has ever used the CaiKote 44 product from good old Caig (of DeOxit fame) for contacts on vintage keyboards...

I've got an early 80s Korg Mono/Poly. Half the keys don't create a sound. The non-working keys are all over the place...so it's not one batch of keys or one bit of the key circuit that busted.

Opening it up, I see that each key presses a big rubber membrane-thing that presses a small circle of conductive rubber against a pair of gold contacts. I'm assuming that it's either the conductive rubber or the gold contacts that are having problems.

I tried alcohol and Q-tips on the gold contacts...to no avail. I'm a little worried about the conductive rubber. I don't know what they can tolerate. Can I use alcohol? Can I use Caig DeOxit?

The only product that really speaks to keyboard contacts is Caig CaiKote 44. It is a silver-based (I think) paint-like stuff that I'd daub onto the conductive rubber to form a new conductive surface.

Does anyone know about this stuff? Is it a good choice for what I'm thinking about doing? Are there other suggestions?

Thanks,

Chip

[bkahuna]

If the black coating is still on the rubber contacts, you won't need the Caikote.

The "gold" contacts on the pcb are actually just copper pcb traces that have been left exposed. They tend to oxidize over time and stop responding. I usually take a pencil eraser to the copper contacts to polish them, then finish them by wiping with alcohol and then applying a VERY thin coating of deoxit. I use isopropyl alcohol on a qtip for the rubber contacts. The only time I ever tried deoxit on the rubber contacts it destroyed them, so I don't go there anymore.

[Mark Hammer]

I've resurrected TV remotes with this stuff: HOME PAGE -- STABILANT but it can be hard to find.

Probably a better bet is this: Rubber Keypad Repair Kit

[jrfrond]

Stabilant isn't hard-to-find, just pricey. We use quite a bit of it here, and the denatured alcohol base won't harm the carbon contacts.

I've tried the keypad repair kit, and it's effectiveness is spotty. Stabilant is the best option, but it won't last forever.

[chipaudette]

Hi All,

I tried the pencil eraser approach (#2 of course). I rubbed the contacts and then wiped it clean with some alcohol. I let it dry, put the rubber contact strip back on there, and then put the thing back together. A couple of the keys now work, but most of the non-working keys are still non-working.

How hard (or not) am I supposed to rub with the pencil eraser. I did use some amount of pressure and I did swipe back and forth a decent number of times. I'm assuming that I worked that approach sufficiently...but maybe I'm really supposed to lean into it and seriously rub. I'm not sure. I didn't want to damage the traces. Should I do it harder?

Chip

[Mark Hammer]

A friend who has a very active studio records to 2" tape for the master, and then does the mixing in the digital domain. All those sliders up until he enters the digital domain have to be dead quiet, though, so he relies on Stabilant. After he turned me on to it, I found a place near me that had a bin of the little half-millilitre "tester" vials for 50 cents a pop, so I bought a couple of fistfuls, often giving them to people as "party favours". I find one vial can let me treat 30-40 pots, eaasily. After stopping by Gruhn's Guitars in Nashville last year, and having lunch with George, I was chatting with one of the tech/repair people there and sent him a few vials to try out on older instruments. I've been impressed with the manner in which it has been able to bring some things back from the dead. There ARE limits on its miraculousness, but within those limits it is a pleasure to use.

And, I'm proud to say, it is a Canadian product.

[bkahuna]

How hard (or not) am I supposed to rub with the pencil eraser. I did use some amount of pressure and I did swipe back and forth a decent number of times. I'm assuming that I worked that approach sufficiently...but maybe I'm really supposed to lean into it and seriously rub. I'm not sure. I didn't want to damage the traces. Should I do it harder?

Chip

It shouldn't take much pressure. The one's that I've done, I've been able to observe a color change of the pcb traces. They go from looking dingy to looking bright, and lighter colored, almost instantly. Perhaps you have other issues. Is there any evidence that there may have been a liquid spill in the past? This can corrode pcb traces or diode leads and leave many non-working keys. Try moving the contact strips around to see if the working keys change with them. If that's the case, then the black conductive coating may have worn too thin to be useful. Usually when that happens, you can "see through" the black to the gray rubber below if you look closely in bright light.

[jrfrond]

I had a long discussion with the Stabilant people about a month ago. Very cool people and know their business inside and out.

Stabilant's formula, albeit in a higher titration, was originally sold as "Tweek" to the audiophile set back in the 80's. Stabilant only sells to the industry now and not consumers, as the auto, avionics and military industries have taken to it tooth & nail. It truly IS some miraculous stuff, and you REALLY need to go to the website and read all of the application notes. It will blow you mind.

I still love DeOxIt, and even Stabilant agrees that it is a great cleaner, whereas Stabilant 22 is a conductivity restorer. We've used both to restore recalcitrant and/or unobtainable tact switches in many old units. It was originally developed for use in recording studios to treat the old problematic Schadow switches seen in many vintage consoles.

I've purchased some chemical injector bottles that have needle applicators to apply the stuff in the cracks of switch cases, etc. I now add a few drops of DeOxIt D100 concentrate to the Stabilant to make a cleaner/restorer solution, and we are are truly giddy about this here (well, all of us techno-geeks anyway!).

A friend who has a very active studio records to 2" tape for the master, and then does the mixing in the digital domain. All those sliders up until he enters the digital domain have to be dead quiet, though, so he relies on Stabilant. After he turned me on to it, I found a place near me that had a bin of the little half-millilitre "tester" vials for 50 cents a pop, so I bought a couple of fistfuls, often giving them to people as "party favours". I find one vial can let me treat 30-40 pots, eaasily. After stopping by Gruhn's Guitars in Nashville last year, and having lunch with George, I was chatting with one of the tech/repair people there and sent him a few vials to try out on older instruments. I've been impressed with the manner in which it has been able to bring some things back from the dead. There ARE limits on its miraculousness, but within those limits it is a pleasure to use.

And, I'm proud to say, it is a Canadian product.

[jbltwin1]

One thing that I have used very succesfully is the little bottles of heater grid repai for the heated back glass in your car. Clean cicuit board as stated with the pencil eraser and clean the rubber pad with alcohol. Then apply and spread evenly the heater grid repair over the pad and let dry 48 hrs. Works pretty damned good and if you buy it at any local auto parts store, it's pretty reasonable.

[Mark Hammer]

I was chatting about Stabilant to a couple of guys repairing our elevators at work the other day, and they were VERY interested; especially since the overwhelming brunt of the servicing they have to do IS electrical contact related.

Whenever I buy some new pots, I usually pop the backs off, apply a few dabs of the stuff as prophylaxis, and then reassemble the pots. I've also had success dabbing tiny amounts to the contacts of budget IC sockets on boards when the ICs were not making full contact. In a perfect world, those budget sockets would be replaced with machined-pin type to assure contact, but it's one helluva lot easier and faster to just lift each chip out, go dab-dab-dab, and stick the chip back in, than it is to desolder and resolder all the sockets.

The DeOxit/Stabilant combination is a very clever idea, and a real one-two punch. As good as Stabilant is, one of its limitations is that it remains viscous, such that you cannot build up layers. If the space between a resistive strip and pot wiper is greater than a certain width, Stabilant isn't going to fix it (so well-used wahs from the original Clyde McCoy era may still need to have thepot replaced)). But in the world of electrons, teeny tiny gaps can be like leaping across the Grand Canyon, and Stabilant can easily plug them up if they are not beyond a certain size. It also cannot counteract any oxidation underneath, which is where the DeOxit comes in.

[bkahuna]

Wow. I've been doing repairs for 20+ years, and this is the first I've heard of Stabilant. Looks like I've got some reading to do on their website. So, it's usable in pots and switches...what about faders? Are you guys using the diluted version or the concentrate?

[Mark Hammer]

Yep, faders too. In fact, the guy who first told me about it uses it for the long throw faders on the MCI board in his studio.

I use concentrate, unless it's getting to the bottom of the vial and I don't feel like opening up a new one. But my buddy uses dilute and is quite satisfied with it.

One of the things I keep reminding people of is that some of the crap inside a pot is not exogenous dirt, but endogenous. Remember that pots and faders can only function because enough pressure is being applied by/through the wiper to maintain contact between the wiper and resistive strip. Over time, that pressure and friction can erode the resistive strip, especially if the wiper is poorly designed and scrapes too much. Where does that material go? It stays inside the pot, and becomes like the gravel on the road that used to be part of the smooth asphalt. Whether the crap on the road came from somewhere else, or from the asphalt itself, it's still crap that creates intermittent contact between your tires and the road, and produces noise as a result.

And as resistive material is eroded from the strip, what is there to take its place? Nothing. Again, those gaps creates momentary discontinuities between the wiper and resistive strip. One of the nice things Stabilant can do is fill in those gaps to prevent discontinuities. As noted earlier, however, there are limits to how big a gap the stuff can fill, because it does not harden in a manner that lets you build up layers like paint.

This is why thorough restoration of electrical continuity in older contact-based devices like switches or pots can require up to 3 elements:
1) Cleaning and removal of outside or inside-derived particulate matter
2) Removal of tarnish/oxidation
3) Liquid "resurfacing" and filling of any gaps

#1 is certainly useful, sometimes pivotal, and sometimes enough. Adding #2 and #3 can go a step further in many instances.

[chipaudette]

Hi All,

Thanks for all the tips. I tried the eraser approach again, but my contacts on the PCB side were already glowing with a pretty nice gold color from the first treatment. So, not too surprisingly, the second hit with the eraser did not bring the keyboard back to life.

At this point, my order of CaiKote 44 finally came in from allelectronics.com. I've been reading your suggestions of Stabilant with great interest and was prepared to get that next, if the CaiKote didn't do it.

Today I finally got some time to work on the keyboard. I read the instructions on the back of the CaiKote, took apart my keyboard (again) and applied it to a few of the dead keys (I applied it to the carbon and rubber pad faces that press to the PCB). After letting it dry/cure for 30 minutes, I put the keyboard together (again) and tried those particular keys. It seemed to work!

So, I took the keyboard apart (again) and applied the CaiKote to the rest of the keys, let it dry/cure, re-assembled the keyboard (again), and tried it out. Total victory! Every key now works. Considering that I had ~20-23 keys not working on my 44-key keyboard, this is a pretty exciting change.

The skeptic in me wonders how long this fix will last. But, at the moment, I'm pretty darned happy.

Victory tastes sweet.

Chip