Sunday, 10 August 2025

Ghosts n Goblins (Bootleg) repair

 This Ghosts n Goblins bootleg just sat on a screen of garbage and did nothing.



I eventually found a 74LS74 with weak signals on the top board near the ribbon cable. Replacing the logic chip allowed it to boot and the sound worked but the sprites were messed up (which I forgot to photograph).

I traced this down to a 2114 ram on the bottom board using the piggyback trick (placing a good chip on top of the suspect one).

 
 
Someone had cut pin 18 and then resoldered it, I guess looking for a different bad ram but now this one is bad. Once replaced that fixed all the issues apart from one.

 

The last issue to resolve is that the board is an amputee, with only two and a half feet.

 
 
That's better.

Thursday, 7 August 2025

Captain America and the Avengers PCB repair

Captain America and the Avengers by Data East, this came in for repair as it was completely dead. While probing around it briefly displayed an error message but then went back to a black screen. This gave me some hope because at least the custom cpu wasn't dead but there are a lot of custom chips.

After heating up it seemed to show a bit more life than it would from cold, cranking the 5V also helped and going high enough it would actually boot. Then as it heated up I was able to lower the voltage a bit but never lower than 5.3V which is still too high for continuous use.

I decided to let it cool down and then run it at 5v while heating small areas of the board with my hot air station (low heat) until it spring to life, to narrow down the area and eventually the chip. I got to the custom chip '75', which is used for I/O (controls) and security and it fired right up.

Usually the repair attempt would end here but thanks to a kind member of the community that had a scrap Fighter's History board I was able to try the '75' chip off their board. At least according to mame source it is 75 but the markings have been sanded off. Also looking at other Fighter's History board pictures online it's possible it could be a 104 chip instead.

 



The bad 75 chip removed and new unknown number unknown working condition chip fitted.
 
With the 5v line set to exactly 5v I fire it up and....
 
 

 
Success!