snakeGrave
Enthusiast
I think I've made some progress with the repair of this board.
reset was high
and halt was reading low
I traced them both back to pin 4 (Reset) and pin 6 (Halt) on an HD74LS14 near the JAMMA edge underneath the "redsun" logo.
pin 3 and 5 on the hd74ls14 were wired together, so I thought it could be an indication that the IC was malfunctioning so I replaced it.
Nothing changed, but while probing earlier I accidentally shorted Reset on the HD74LS14 to an adjacent pin and it got this thing moving I guess. It boots with garbled graphics and I can coin up but it is not really playable.
It seems like the BG ram and OBJ ram have crapped out based on the startup diagnostic shown in my photo. I'm going to start poking around the 4 surface mount HM628128A at the end of the board opposite the JAMMA edge.
Also, I know I should have taken ekorz advice and checked the prog roms earlier but where is the best place to find the appropriate files. Would these be the (2) 4MB files from the '1945 Part-2 (Chinese hack of Battle Garegga)'
The 1945 part-2 files I downloaded do vary from the ones on my board.
reset was high
and halt was reading low
I traced them both back to pin 4 (Reset) and pin 6 (Halt) on an HD74LS14 near the JAMMA edge underneath the "redsun" logo.
pin 3 and 5 on the hd74ls14 were wired together, so I thought it could be an indication that the IC was malfunctioning so I replaced it.
Nothing changed, but while probing earlier I accidentally shorted Reset on the HD74LS14 to an adjacent pin and it got this thing moving I guess. It boots with garbled graphics and I can coin up but it is not really playable.
It seems like the BG ram and OBJ ram have crapped out based on the startup diagnostic shown in my photo. I'm going to start poking around the 4 surface mount HM628128A at the end of the board opposite the JAMMA edge.
Also, I know I should have taken ekorz advice and checked the prog roms earlier but where is the best place to find the appropriate files. Would these be the (2) 4MB files from the '1945 Part-2 (Chinese hack of Battle Garegga)'
The 1945 part-2 files I downloaded do vary from the ones on my board.