Re: Picture but no sound!

[MrPagel]

(Okay then.  Please excuse me for veering slightly off-topic, as I have replaced the 128 with a 64.  I'm having trouble finding a C64 forum that will let me log on.)

Anyway, I got a C64 yesterday, via Craigslist.  It will work fine for 20 minutes, then shut down.  Blank screen, no sound or response.  When I reboot, it stays on for just a few seconds then shuts down again.  Something is overheating?

I also notice that the sound is a bit soft, and that the background noise -- that light "whirring" that kind of sounds like a small electric motor or fan -- is a bit loud.

Oh, and the basic algorithm for the paddle-theremin is:
POKE 54273, 255-PEEK(54297)
Voila!

[BigDumbDinosaur]

Sounds like the classic symptoms of a flaky power supply.

[Hydrophilic]

I had that problem with one.  I was able to 'fix' it by replacing the 5V regulator on the motherboard and adding a heat sink to it -- that thing got hot!!  I assume the real problem was a chip (or other component) had a partial failure and was drawing too much current.  Never did find the real problem, but it worked reliably after the 'fix' for over a year... finally got a C128 and put it to rest.

Actually I saw it a few weeks ago when I was digging around for boxes for Christmas gifts.  So I think I know where it is, just a moment...

Looking at it now, I also put a heat sink on the 12V regulator  (near bottom middle).  And an extra heat sink on the 5V one (near the power switch / joystick ports).

Heh, heh.  You can see it has gather some dust and rust while being in storage.  Anyway, it's something cheap you can try, or it may be the power supply like BDD said.