Obtained a beat up stored board for cheap. Pretty dusty but all the CPU EPROMS seem to be there!
After blow dusting and going over the board with my trusty PCB dusting brush, First thing I noticed is possible broken traces, so I took some time to go through all questionable traces with my continuity tester for good 2 hours.
Upon powering the board… black screen… hmmm… further inspection, I notice some potential shorting from bent IC pin’s at the bottom of the board. So I spent more time trying to straighten out pins as much as possible and make sure none are shorting.
Still black screen, I did some research and found out possibly the main encrypted CPU battery being 30+ year old probably went bad, thanks to good information about resurrecting the board from The Dead Battery Society http://www.arcadecollecting.com/dead/ & JAMMARCADE http://www.jammarcade.net/ I’m able to burn the proper decrypted 5 & 7 EPROM as well as swapping out for standard Motorola 68000 CPU
The board came alive!
Now, another problem, I get no sound, turning the potentiometer for the audio and hear just humming noises. Might be issue with the Z80B CPU?
I end up replacing it but still no sound, so I take a look at the top of the board, and found the potential problem near the Z80B CPU traces seem like they got pretty deep scratch from something impacting it. Continuity tester confirmed this and find 2 traces bad. I simply jumpped it with a wire. Audio’s ALIVE!
Board seems to be working properly, and I will be doing a full test run with few weeks.
Also at the same time I have acquired Sega Altered Beast, still working in it’s original form with the battery intact. I lucked out on this one!