Fixing a RIDICULOUS Commodore 128 Keyboard Fault

[@MoreFunMakingIt]

Thank you for this video! I just took apart my first c128 keyboard and was a little baffled to find a tiny spring floating around inside. Sorted now!

[@BasicBitesCA]

My pleasure! Reportedly, without that ground connection, static discharge into the metal keyboard plate can cause damage to the CIA chip... and I doubt it was a coincidence that the CIA chip reading the keyboard on that particular C128 had gone marginal. -- JC

[@MoreFunMakingIt]

@@BasicBitesCA Thats so interesting! The CIA on this 128 has also gone marginal faulty with just a single row in the matrix missing altogether. I wonder if this was a grounding issue?

[@RacerX-]

Nice overview, it is much appreciated. I have 2 128s and thankfully I have not had to take apart the keyboards. I have had to on several Amiga 500s and they basically use a similar setup, albeit not a PCB but a thin membrane. tons of screws and no fun. But the puns make for some funs... 🤣

[@jeffreyphipps1507]

When I desolder the toggle keys, I add detachable wires to save time in the future.

[@BasicBitesCA]

Good plan! I didn't, although I hope not to have to remove a keyboard PCB more than once in a blue moon. 😊 What do you solder on to make the wires detachable: some sort of miniature alligator clip? -- JC

[@jeffreyphipps1507]

@@BasicBitesCA I wish I could say I made a fancy connection, but I often have USB cables that are bad at one end or the other and don't throw them away (just in case 🤣) and I end up putting the male end on the key and the female end on the board. Maybe not elegant. Soldering them back is easier. I do that when I don't expect to take it apart again. However, I have a "test bed" system for several Commodore systems and I don't want to bother when I have to detach the keyboards that seem to inevitably need repair (the carbon pads are nearing EoL). If I choose to change out those keyboards with mechanical keys, I'll probably won't need to bother.

[@BasicBitesCA]

@@jeffreyphipps1507 Thank you for the information! I have a half-destroyed breadbox C64 that I also use as a "test bed", and might just play around with making the toggle key detachable on there. -- JC

[@psyolent.]

pound the pound key. not bad. good vid thanks for sharing.

[@jm131719]

Thanks for the puns...

[@BasicBitesCA]

My pleasure! No need to thank me. A good pun is its own re-word. 😎 -- JC

[@HAGSLAB]

Good puns 😆

[@BasicBitesCA]

Thanks! 😏 -- JC

[@peddersoldchap]

Hi. Could liquid graphite be used to reconstruct the pads? Also, thank you for the video.

[@BasicBitesCA]

My pleasure; you're welcome! In regards to reconstructing the pads -- in cases where it's certainly the PCB that has the issue, versus the conductive rubber on the key -- I know that conductive carbon paint is a thing that exists, but I have not experimented with it myself. Some of the other great keyboard repair videos on KZbin might have more information on that. -- JC

[@wingedcatgirl]

@.@ How in the world did that spring get there? If they're sealing the keyboard so intently, you'd think they'd have a tighter manufacturing process than that...

[@BasicBitesCA]

Exactly! As a Japanese manufacturer, Mitsumi can usually be counted upon to meet a certain bar of quality, so I'm chalking this one up to an anomaly on what was probably a manual assembly line. -- JC

[@pimpi1]

How can i fix the black carbon contacts?

[@BasicBitesCA]

Good question. I would strongly recommend searching other videos on the subject, because I've never done it. That said, if I had a C128 Keyboard PCB with degraded carbon pads, I would probably use the opportunity to experiment with conductive carbon paint and see if that fixes them. (For a C64 PCB, I would more likely just buy a working one, since '64 keyboards and their parts are still relatively cheap and plentiful.) -- JC

[@homerbyrd1555]

p̾r̾o̾m̾o̾s̾m̾ 👍