Hi guys, my first time here and I was wondering if anyone has any ideas to narrow down my search for a fault with a PAL NES that has a problem outputting video.
The system loads the cartridge and the music plays normally, I actually get a flash of the game picture for half a second or so when it's powered on and then I get a black screen thereafter.
I've swapped out the PPU, CPU and the Power/AV box which are all working on another system with no problems. I cut pin 4 on the CIC to make sure it wasn't playing a part. On the scope I believe I'm getting a genuine black screen produced (not a problem picking up a dodgy signal). Because of the cartridge tray setup it's a challenge to take any measurements with a game running so I thought I'd see if anyone has come across anything similar and can point me in the right direction and if I should start looking at the RAM, Logic chips or individual components (which all visually appear fine).
The system loads the cartridge and the music plays normally, I actually get a flash of the game picture for half a second or so when it's powered on and then I get a black screen thereafter.
I've swapped out the PPU, CPU and the Power/AV box which are all working on another system with no problems. I cut pin 4 on the CIC to make sure it wasn't playing a part. On the scope I believe I'm getting a genuine black screen produced (not a problem picking up a dodgy signal). Because of the cartridge tray setup it's a challenge to take any measurements with a game running so I thought I'd see if anyone has come across anything similar and can point me in the right direction and if I should start looking at the RAM, Logic chips or individual components (which all visually appear fine).