Got this 1941 : Counter Attack (Japan release) B-BOARD for repair:

Game had some graphics issue on backgrounds:

I swapped the C-BOARD with the one from a Street FIghter II : World Warrior which mounts the same ‘CPS-B-05’ ASIC :

GFX issue disappeared so the fault was in the C-BOARD :

I was asking by owner to transplant the ASIC from the donor C-BOARD to original one, here’s a step-by-step collage:

The operation was successful :

Board 100% fixed and aesthetically like genuine, appearances count too…

Received from USA this Pac-Mania ROM board (Namco System 1 hardware) for repair :

According to the owner board played fine but mute, this was confirmed once powered it up.Using my audio probe I could hear sound on the input (pin 2) of the two LA4460 amplifiers but nothing on outputs:

At closer inspection one of them was literally blown up:

So I proceeded to remove both:

and installed two new spares and some thermal compound on heatsink:

Sound restored and board 100% fixed.End of job.

 

Update:

After converting this board to Splatterhouse I found that voices and other sound FXs were missing:

I quickly pinpointed the fault in a bad TL084 OP-AMP, replacing it cured the issue: