Tuesday, 29 May 2018

Popeye pcb (bootleg) repair

I bought this Popeye bootleg pcb in a lot of faulty boards, it included the worse jamma adapter I've ever seen. It's made from another cut up pcb, anyone know what game it was?


The board was working apart from the character layer of the graphics, making the text scrambled and blue blocks appear over the background and other sprites.



I didn't notice at first but blue and green were also switched, this was an issue with the adapter though and not the board.

The first thing I did was dump all the eproms and make sure they matched the ones in mame. Eprom 5 failed but this was a red herring as it was fine even though it's not in mame. :)

This did lead me in the right direction though as the data causing the issue is stored on this rom, it looked much better with it removed from the board. So I started looking around this area, I piggybacked a 2114 ram @ F8 and things looked much better, leaving the ram in place and power cycling the board completely fixed the issue.



I replaced the bad ram and made a new jamma adapter.




The colours are now correct, repair complete.

Saturday, 26 May 2018

Aliens pcb repair

I bought this Aliens pcb as faulty with the error bad i3.


Someone had already replaced and socketed i3 (a 6116 type ram) and this made no difference to the error.

Checking the very nice schematics there was pretty much only one thing that could be the issue.


The 051960 konami custom chip. I had one left in my little box of customs, in unknown working condition. It came from a Main Event board that I'll be harvesting for more parts later in the repair.

Anyway back to the 051960


Replacement custom in place.



Yay the ASIC is good.


This just left the sound section, four capacitors were broken off the board.


The electrolytics I have plenty of but I didn't have the correct value for the mylars so I dug out the scrap Main Events board and pulled two from that.


Sound fully restored, repair complete.