segasonicfan
Camel Slug
- Joined
- Feb 3, 2006
- Posts
- 517
There's a CPLD on the left hand side (not shown on your photos there) - that does the address decoding for the M1 ROM. The M1 ROM is just above it. I would check all the connectivity out around that area. That CPLD takes 4.3v from the middle of the two diodes which power the board. Look on under side of the PCB where the 2 diodes join - There should be a trace which leads off and is jumpered (probably with a tiny particle of solder) to a trace which goes to a via. Check the connectivity around there to ensure that 4.3v is getting to the CPLD. You could reflow the solder on M1 and that nearby CPLD. I presume you've narrowed it down to this board by swapping the top and bottom boards etc?
Thanks so much for this!! (And the thread in general). I have this exact same issue with my old version 161-in-1 (no sound but else seems working). I did caps, new regulator, etc. but issue remains. Ill try reflowing M1 chip and CPLD but has anyone tried JTAGing that chip? If I could get the code off its not hard to get a new one.
-Segasonicfan