I am reviving a VIC-20 REV-E (board 1001006). It is a very early VIC-20, not a VIC-1001.
I have socketed the entire board and replaced:
- All the electrolytic capacitors
- 3 failed glue logic chips
- 3 failed 2114's.
The board is finally alive, but I am now seeing dark bands slowly rolling down the screen (using NTSC composite).
See picture below.
My other VIC-20 with board 324003 with the same VIC 6560 chip, same composite video cable, and same 9VAC 1.5A power supply does not produce this problem.
I have not yet replaced the rectifier and the regulator, as I'd like to first hear some savvy advice from you guys.
Thanks in advance!
Here is the picture. Note that the darker horizontal bands are THE problem and are not caused by my camera.