I recently hooked up my Mortal Kombat II PCB that I had around for 5+ years and never hooked up. It just had these plastic divet things for putting screws through to mount it in a cabinet. I just sat it flat in my arcade supergun box and sometimes it worked fine. Other times all sorts of things happened. For awhile sometimes player life bars would randomly not go up all the way at the beginning of a round. Other times after winning a round the winning player would change characters to match the loser. Later on the game would just crash (resetting though) at various points. I had observed it never did this when I sat it on edge as if it were mounted to the side of a cabinet. But it didn't fit in my arcade box this way, just about a half inch too tall to fit. I ended up solving the issue after removing the divet plastic things and putting 4 spare pcb feet on it (2 middle, 1 on each end opposite corners). I need to get some more, I though I had some around somewhere but I can't find them. Anyway has anyone else ever experienced weird arcade game glitches do to something like this? I imagine it's not such a big deal with smaller pcbs or thicker ones. But MK2's T-Unit hardware is pretty long and heavy particularly with the memory expansion board it requires putting additional weight on the center of the board.
I guess so, I haven't examined the board closely to determine this. Hadn't thought of that being the case. =(
Well, it's indication of a bad connection. Whether this is a cracked track, dry joint or poor connection in a chip socket is anyone's guess. Don't forget that glitches can be due to the board receiving insufficient/too much voltage too, though!
