This is the place to discuss our glorious C64/128 machines and their very active scenes. Other C= 8-bits welcome, too!
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smb123w64gb

by smb123w64gb posted Tue Jun 25, 2019 4:57 pm

So I've had this c64 for a bit, when i did some de yellowing put it back together and it hasn't been working. I suspect this jerryrigged capacitor on the cpu is suspect. This c64 has worked in the past. If anyone has some good ideas where to start id love there hear it.

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Zippy Zapp
CA, USA

by Zippy Zapp posted Tue Jun 25, 2019 5:03 pm

When you say it doesn't work is it black screen or something else?

For black screen start here:

1. Check the fuse
2. Check the voltages of the PSU
3. Remove the SID chip (not needed to startup)

4. After you have tried those then try a dead test cart if you have one.
5. Try swapping the 6526 CIAs in the upper left.

It could be related to the mods but hard to say. If it is a black screen they are the hardest to troubleshoot. But if the board looks clean with no obvious damage then it is probably fixable with the right chips.
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smb123w64gb

by smb123w64gb posted Tue Jun 25, 2019 5:23 pm

Oh also the vic2 has this...
Based off of this its adding a cap to A6, Ill see if thats what is needed on the cpu
And that did not to anything to bring it back.
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obitus1990
New Orleans, LA, USA

by obitus1990 posted Tue Jun 25, 2019 5:53 pm

What is the ASSY. no of the PCB? It looks to be a rather early one. There seems to be another jumper on the IC on the bottom left, which I think has something to do with the reset signal in early boards.
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smb123w64gb

by smb123w64gb posted Tue Jun 25, 2019 7:36 pm

obitus1990 wrote:What is the ASSY. no of the PCB? It looks to be a rather early one. There seems to be another jumper on the IC on the bottom left, which I think has something to do with the reset signal in early boards.

Its a ASSY 326298 Rev A
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smb123w64gb

by smb123w64gb posted Tue Jun 25, 2019 8:30 pm

Hey if anything id love to throw a new PCB in this if all the chips are working, and can be in a old breadboard case.

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