Helllooo wonderful peeps! Just getting started into learning to repair arcade boards and stupidly thought i'd try my hands at a final fight board cuz I always loved the games, so i bought a 'broken' one off ebay without doing research realizing these things die if the wind blows. Fun!
So originally there was no audio, no video, nothing. i found out there was a missing ferrite bead at the FB1 location. I put a generic bead there (about 5ohms) and all of sudden i'd get sound which sounded like 5 punches real fast and someone grunting like they were knocked out and nothing else. After fishing around and popping some rom chips, i found out rom 2 chips were blank (funny enough 2 chips that were NOT original). I re-flashed them and now i get full audio, I can hear the game starting, Playing, can input coins and press start and hear it all functioning great. Problem is I cant see anything. black screen. I use a supergun mini gun into an OSSC which goes into a testing LCD monitor. The OSSC is reporting some high sync numbers (31.25khz and 119.27h at 262p) which seems almost like it's double what it should be. (granted the ossc could just be wrong). Anyways I've searched and searched seen it called out probably the C board as it generates the sync. I will say whoever had this board before me replaced the 16mhz crystal on the A board with a new one, not sure if they knew more than I know or just took a random shot in the dark?
As I don't have any other CPS1 boards I cant check if its the A board or C board, and cant find anyone having exactly this issue with a supposedly double speed sync. I've checked all the traces from the CPS chip on the c board they all seem to go to their correct areas. There is one bent pin on this chip (I don't even understand how only 1 pin is bent?), but its continuity checks out (couldn't tell if you maybe its broken inside the plastic or not though).. Also there's no bridging between the pins next to it that I can detect (checked 3x times). I've checked the rest of the pins and they all seem to be down on the board (nothing pulling up that I can detect).
Any thoughts or other suggestions?
So originally there was no audio, no video, nothing. i found out there was a missing ferrite bead at the FB1 location. I put a generic bead there (about 5ohms) and all of sudden i'd get sound which sounded like 5 punches real fast and someone grunting like they were knocked out and nothing else. After fishing around and popping some rom chips, i found out rom 2 chips were blank (funny enough 2 chips that were NOT original). I re-flashed them and now i get full audio, I can hear the game starting, Playing, can input coins and press start and hear it all functioning great. Problem is I cant see anything. black screen. I use a supergun mini gun into an OSSC which goes into a testing LCD monitor. The OSSC is reporting some high sync numbers (31.25khz and 119.27h at 262p) which seems almost like it's double what it should be. (granted the ossc could just be wrong). Anyways I've searched and searched seen it called out probably the C board as it generates the sync. I will say whoever had this board before me replaced the 16mhz crystal on the A board with a new one, not sure if they knew more than I know or just took a random shot in the dark?
As I don't have any other CPS1 boards I cant check if its the A board or C board, and cant find anyone having exactly this issue with a supposedly double speed sync. I've checked all the traces from the CPS chip on the c board they all seem to go to their correct areas. There is one bent pin on this chip (I don't even understand how only 1 pin is bent?), but its continuity checks out (couldn't tell if you maybe its broken inside the plastic or not though).. Also there's no bridging between the pins next to it that I can detect (checked 3x times). I've checked the rest of the pins and they all seem to be down on the board (nothing pulling up that I can detect).
Any thoughts or other suggestions?
