johndias Posted September 18, 2020 Share Posted September 18, 2020 Hi all, my new power supply from Ray arrived today so I got a chance to boot up for the first time. System comes up, no problem, but the keyboard ... probably 80% of the keys don't work. I had pulled them and cleaned them while I was retrobriting the case (and lost one spring - anyone got a spare?). I saw another thread @carlsson recommended swapping the 6522 chips, which I will do. What else can I check? Quote Link to comment Share on other sites More sharing options...
carlsson Posted September 18, 2020 Share Posted September 18, 2020 Is there a pattern to which keys are not working? Like it was mentioned in the other thread, every second key worked and the rest didn't. If you have a massive fail of up to 80%, sure it could be a toasted 6522 but it makes me wonder what other causes it could be. In case you own a C64, the keyboard is mechanically (*) and electrically compatible with the VIC-20 one so you could swap keyboards to rule out sources of error. (*) The white C64C keyboard may have different mounting points so it would be difficult to fit physically, but loose out of the case it works the same way. 1 Quote Link to comment Share on other sites More sharing options...
johndias Posted September 19, 2020 Author Share Posted September 19, 2020 I pulled the keyboard PCB out and cleaned it with IPA. Then I plugged it back in and used a wire to jump the contacts to see if that would respond. The keys did (I didn't do a complete test but enough to convince me that I had a mechanical problem). Then I took a plunger (the commodore key) and used it to connect each of the contacts. No bueno, the key presses did not show up. So, I think my plungers are bad, what to do? These are NOT the rubber dome ones but rather like this one Quote Link to comment Share on other sites More sharing options...
johndias Posted September 19, 2020 Author Share Posted September 19, 2020 17 hours ago, carlsson said: Is there a pattern to which keys are not working? Like it was mentioned in the other thread, every second key worked and the rest didn't. If you have a massive fail of up to 80%, sure it could be a toasted 6522 but it makes me wonder what other causes it could be. In case you own a C64, the keyboard is mechanically (*) and electrically compatible with the VIC-20 one so you could swap keyboards to rule out sources of error. (*) The white C64C keyboard may have different mounting points so it would be difficult to fit physically, but loose out of the case it works the same way. There's no pattern, that I can determine. The working ones are scattered about. Quote Link to comment Share on other sites More sharing options...
carlsson Posted September 19, 2020 Share Posted September 19, 2020 There are a few smaller variations on the keyboard mechanism, but all have some sort of plungers. I believe you can use graphite spray or draw with a pencil on the rubber to make it conductive, but if most (80%) of the plungers don't register, it must be quite worn. Quote Link to comment Share on other sites More sharing options...
johndias Posted September 19, 2020 Author Share Posted September 19, 2020 Hmm, I have some graphite powder and was attempting to make conductive paint for an electroplating project - I might play around with that and see if I can re-surface those plungers. Quote Link to comment Share on other sites More sharing options...
johndias Posted September 19, 2020 Author Share Posted September 19, 2020 Oh man, rookie mistake! Short story, while I thought the contacts were clean I put them under my microscope and realized there was corrosion on most of them. So, with extra diligence I cleaned them all up and for kicks tested the resistance on all of the plungers (they were all around 100 ohm which I guess is good?) and tested - all the keys work! Well, except for the Commodore key, for which I lost the spring. Anyone know where I can buy one? 2 Quote Link to comment Share on other sites More sharing options...
+evg2000 Posted September 19, 2020 Share Posted September 19, 2020 cool! what did you use to clean off the corrosion? Quote Link to comment Share on other sites More sharing options...
johndias Posted September 19, 2020 Author Share Posted September 19, 2020 Just now, evg2000 said: cool! what did you use to clean off the corrosion? IPA and a paper towel. I think the problem before is that I was using a non-cotton fiber swab like the ones here and it wasn't doing much scrubbing. They're great for general grime and cleaning tape and disk heads, though. Quote Link to comment Share on other sites More sharing options...
+evg2000 Posted September 19, 2020 Share Posted September 19, 2020 thanks Quote Link to comment Share on other sites More sharing options...
carlsson Posted September 19, 2020 Share Posted September 19, 2020 Probably someone has spare keyboards in parts from where you could source a spring if that is all you're missing. I suppose measuring an existing one might allow you to find somewhere selling springs only, though I don't know if hardware stores have that. Quote Link to comment Share on other sites More sharing options...
johndias Posted September 20, 2020 Author Share Posted September 20, 2020 3 hours ago, carlsson said: Probably someone has spare keyboards in parts from where you could source a spring if that is all you're missing. I suppose measuring an existing one might allow you to find somewhere selling springs only, though I don't know if hardware stores have that. I've had to match springs before, it's challenging. There are online places that sell springs. That's my last resort, I'm hoping to find a kind soul with a spare VIC-20. Quote Link to comment Share on other sites More sharing options...
johndias Posted September 20, 2020 Author Share Posted September 20, 2020 Found replacement springs here - http://retroleum.co.uk/ At a very reasonable price! Quote Link to comment Share on other sites More sharing options...
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