Working on a non-booting Gorgar, and I'm starting to lose my mind a little. Here's a rundown. Hoping someone can offer up some advice!
Powers up to GI, no boot, displays have glow, but blank. Checked fuses, Solenoid fuse blown, all others fine. Checked power supply voltages, 5.08V and 12V unreg seem fine coming off the power supply board. When the game is powered up, both LEDs on the MPU light up immediately, and stay lit. Power-cycling on/off quickly produces no change. A few times while turning the game on/off quickly, suddenly the relay on the driver board would click rapidly (insert lights flashed with it) and the displays would go crazy with junk digits/segments. This was rare, but happened a handful of times. A sound was emitted with it briefly. I have a video for reference, if desired.
- Verified voltage at CPU power connector 1J2 (under load) as follows:
12V unreg = 10.52 VDC
5V #1 = 4.82 VDC (note when connector is unplugged, this is 5.08 VDC)
5V #2 = 5.08 VDC
5V #3 = 4.82 VDC (note when connector is unplugged, this is 5.08 VDC)
- Interconnect replaced (both Male/Female)
- ROMs resocketed to get rid of dreaded SCANBE sockets
- Replaced RAM IC13 since that was a socketed chip
* No change after performing the above *
Following advice in other threads (including vid's guide, pinwiki, etc), I have tried several other things:
- Swapped in spare Power Supply I had, no change (correct voltages)
- Swapped in a spare System 6 MPU board I had around, same results
- Disconnected the Driver Board completely, and attempted diagnostics tests with MPU-only. Results were erratic, but after trial and error, pressing the Diagnostic switch on the MPU caused the LEDs on the board to flash and go out. Per info I found, this could indicate a Driver Board issue.
- Swapped in a spare, good Driver Board I had and powered up the game
* Game appeared to boot, and Display showed the Game ID, so I thought I solved the issue. Power-cycled the game on/off to get it to boot... and it immediately started doing the same thing it was doing at the beginning. Dead game, just GI, displays blank, both LEDs on the MPU locked on.
... What the heck happened? It's as if the other Driver board solved the issue, but then was immediately murdered somehow? I'm confused.