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Re: With the vic-ii removed...does the floppy work?

Posted: Sat Mar 27, 2021 10:59 am
by finepie
I took apart the keyboard and gave it a good cleaning. No visible wear and tear, and I tested the keys with a multimeter, so they're definitely confirmed working now. So I'm pretty sure it's the CIAs. Shame they are so freaking expensive! Apparently there is a modern replacement (JCIA) but that's not yet released.

@rmzalbar thanks for the tip, I'll give them a good cleaning and test continuity. I've checked before, but as I've learned by now, you really need to test three times to be sure!

Re: With the vic-ii removed...does the floppy work?

Posted: Sat Mar 27, 2021 1:26 pm
by finepie
WOAH baby, it always pays to double-check everything! There was a subtle broken trace on the keyboard on the PA7 line (it almost looks like physical damage, no idea how that can have happened). The diagnostic cart confused me, because it reports both CIAs as failed if you don't have a harness, which I didn't realize (ran it in VICE to confirm). So the CIAs were a red herring, thankfully I hadn't ordered replacements yet.

IN OTHER WORDS, after over a month, probably 20+ hours of work, and maybe $100 or so on parts and tools, I HAVE A WORKING C64!!!! I'm SO happy that my persistence paid off. This project will still continue (SID still needed, some heatsinks, a PSU saver, jiffydos etc), but the repairs are COMPLETE!

Thanks SO much to everyone for all the tips and guidance, especially gyro gearloose! Hopefully this thread proves useful and/or encouraging to someone else down the line. This has been a really fun learning experience.

Take that:

Re: With the vic-ii removed...does the floppy work?

Posted: Sat Mar 27, 2021 3:56 pm
by Gyro Gearloose
Diagnostic cartridges are simply a tool, with their own strengths and weaknesses and blind spots. Like any tool, really.

Perseverance isn't just a rover on Mars, it seems!

Well there we go, a happy end.

Oh and you're welcome!