No Sound and SYS 54301 Returns to READY – Need Help Troubleshooting

[sokot666]

Hello,

I built this version:

https://www.pcbway.com/project/shareproject/W160781ASB18_Gerber_1790f9c8.html

Unfortunately, it doesn't work completely. There is no sound, and after entering SYS 54301, the computer simply returns to the READY. prompt.

I've tested it with two different Raspberry Pi Pico (RP2040) boards and on two different Commodore 64 computers, and the behavior is exactly the same in both cases.

I'm starting to suspect that I may have received faulty 74CBTD3861 chips, as I bought them from AliExpress, but at this point I'm not really sure anymore.

I've checked all the solder joints very carefully. I also have some experience soldering small SMD components, so I don't think that's the issue.

I decided to post here as well in case I'm overlooking something obvious and the solution is much simpler than desoldering everything and starting over.

If anyone has any idea what could be causing this, I'd really appreciate any suggestions on what to check or try next.

Best regards,

Marcin

[frntc]

The only obvious reasons, but I assume you got these right, is choosing the right firmware and checking the soldering. Unfortunately the CBTDs from Ali sometimes seem to be fake (other people reported problems before). You can test if the Pico is running at all, by pressing reset for more than 5 sec (the LED should signal that it changed the default bus timings).

(I'll convert this to a discussion, as it's not an issue that requires a fix of SKpico HW or SW)