Great people of the forum, a quick update - this board is now 100% working!!
After ya'll helped me undo my short to ground issue I was able to get back to trying to solve the remaining issues (not caused by me). I read a bunch of repair logs, looked through the MAME source code and eventually was able to fix it... though I got lucky on the sprite issue.
Here are the issues I fixed:
Issue: random sound effects were still missing after doing full shotgun recap and installing a working HA13001
Solution: using logic probe and cross-ref the schematics found that pin 23 was stuck low on YM-2203 at 14E while the sister chip at 13E showed constant activity. Decided to make an audio probe based on inspiration in this great
video by 8-bit Manshed to prove my theory. The ghetto fabulous audio probe is really handy! Anyway, socketed and replaced the chip at 14E and boom - Sound restored completely!
Issue: screen orientation was wrong
Solution: for some god unknown reason, the DIP switches were all destroyed. Like someone had purposely broke them off (it was the 80s so I assume cocaine was involved). Installed new dip switches and set them accordingly to fix orientation and other defaults.
Issue: Character sprites were screwy
Solution: With the sprite issue I had multiple pages of schematics to try and digest and I must have probed half the chips on the graphic board related to sprites ROM/RAM and they all "seemed" ok. Worse still the board has a ton of Fujitsu chips which my understanding is they are all shit from this era. After putting the board away for a spell, I pulled it out again this weekend and I had never thought before to look at the jumper wire. My working board has the same exact jumper wire so I assumed it was a factory mod. The solder had broken loose on the chip at 14M!!! A drop of solder on the jumper wire restored the sprites! I guess it was causing issues feeding into the line buffer (right?
). Does anyone else have that jumper wire on their board? I have it on both of mine so I can't imagine that was a coincidence repair done in the field was it?
Thanks again guys for the advice to help get me back on track. Very happy I was able to get this sexy beast back in action.
