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Old 21st Jan 2019, 10:43 pm   #1
qsilver
Retired Dormant Member
 
Join Date: Jul 2010
Location: Carlisle, Cumbria, UK.
Posts: 66
Default Commodore 64 Garbled Screen

I got the old C64 out a while back, wanting to look into doing some vintage programming. It was all going well for an hour or so when the system froze completely.

I turned it off and back on, and got the blue border but the middle was filled with moving colourful symbols.

I had a quick search online and found that it could be the PLA which can become faulty if left for a long period of time unused and then switched back on.

Based on this, I decided to get a new PLA, so I bought the PLAnkton and a socket and fitted it into the board.

Powered up again, and the problem is still there however now the patterns have stopped moving.

I'm not sure where to go now. It could be RAM or Colour RAM i believe, but I'm not very experienced at computer or logic repair. I'm used to soldering etc, I do a lot of vintage audio restoration.

Any help would be appreciated I'd love to get it going again if I can. I've checked the power supply voltage just in case and the power supply is giving 5.3VDC and 9VAC. The internal voltage regulators are also working well, giving me 5VDC and 12VDC.
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