Commodore 64 displaying colored letters

[y-bot]

I'm testing out my pile of Commodore 64s and one of them displays each letter a different color. Is there something wrong with it or did someone modify it to do this on purpose?

y-bot

[Wookie]

Sounds like the color RAM is messed up, which I suppose could be done intentionally.

[y-bot]

Thanks for the info. So far I have one that works, one with a bad keyboard, the weird color one and 4 that display nothing. 1 out of 7 is not very good. I hope I have better luck with the other 10 or so I have. Anyone need any parts? The broken ones are going in the trash soon.

y-bot

[Pete Rittwage]

Most common failure in the C64 is the PLA chip (82LS100) or bad RAM chips due to power supply floating out of spec. You can swap between the units if it's socketed to find out. Either of these issues can cause crazy colors.

Try them all with a different power supply first, because a bad one will fry all your C64's in short order, which may have already happened.

[Thrillo]

At least take out the SID chips before you trash 'em; they're in high demand...

[crazyjackcsa]

At least take out the SID chips before you trash 'em; they're in high demand...

Really? Can you attach a dollar amount to "high demand"?

[scooby105]

Really? Can you attach a dollar amount to "high demand"?

Looks like $15-25 according to eBay prices.

[DefaultGen]

.....

[y-bot]

The final score is 5 working and 13 non-working Almost all of the non-working ones display a blank screen. I'll probably strip some parts off of them before I trash them.

y-bot