I am trying to remedy a fault caused by me years ago. My C64c (PCB ASSY NO. 250469) was working fine until one day I had it running with the case open and I was (trying) to measure the +5v line (to see how healthy the PSU was going). Then I accidentally shorted the power plug (don't know which pins) and the 64c went dead. Now when a (known-good) PSU is connected and power switch is set on, the power led lights up but there is no picture.

The 9v AC is present in the user port. The +5v (measured from the av-port) seems low, 4.74v.

Any tips on how to proceed? The fuse is Ok and there is nothing visibly bad on the board.



Plugging in a game module gives very strange picture:

In case somebody comes across this thread later: the fault was located to one of the two RAM chips (faulty one got VERY hot very quickly when the machine was switched on). New RAM chips were easy to acquite and were soon replaced (de-soldered old chips, installed sockets and put new chips in) and now the 64c is working again!
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Nice job, Always glad to hear of a restored 64.
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Nicely done - I did that a while back on an older machine (1983 I think) and it cooked my PLA chip. Had to pull one from a parts board - but that fixed my issue.

Nice find!
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