11-21-2025, 06:54 PM
(11-17-2025, 01:24 PM)admin Wrote: Check your solder joints one by one. If you used the 'zip' soldering method where you quickly drag the soldering tip while applying solder to the pins of the chips it is possible to bridge two pins, and also possible to miss a pin.
The screen issue you talk about is most common caused by the PLA, but can be the RAM. If you are using sockets, it's possible that a socket is not making a good connection. That is really rare, but I have seen that before.
Hi,
Follow-up. I replaced the 6510 MPU (U7) with an new chip (MOS replacer) and the board is not freezing-up anymore. Now I get "bad user port" and "bad U1" (CIA) on start-up most of the time. I do get a clean diagnostic test occasionally. It seems to run ok when I play some games or run basic programs. Will keep working on it. Need to try the SD2IEC card reader next.