Yet another G.I. Joe PCB on the bench from the five faulty ones received from Portugal some time ago :
Board was in good conditions but someone harvested parts from it.In particular the thee 6264 SRAM (part of tilemap circuit) were missing:
As well as the sound ROM @7C and the 62256 SRAM @2D always in audio circuit :
I installed the components and sockets too where needed.When I powered the board up I was greeted by this screen filled with letters :
Usually this kind of issue on Konami boards means there is some trouble in the tilemap generation circuit so I made a visual inspection and found a couple of severed traces on solder side:
Finally the board executed the self-test but two devices were reported as bad :
The one @2D was the 62256 RAM that was missing while @3E lies the custom ASIC ‘054539’ (which is a PCM sound generator ), both ICs share same address/data bus.
At a closer inspection some pins of the custom were lifted so I promptly refowed them.The board successfully booted into game with no further issue.
Yes, yet another G.I. Joe PCB fixed (hopefully not the last one…)!