LyonsArcade
Well-known member
Repair Log: Strangest Pac-man problem I've ever seen
So, I've got a Ms. Pac man that I've been having issues with. The board works fine as a pacman, but when you add the daughtercard and ribbon cable, it won't boot (keeps resetting).
So, I tried 5 different ribbon cables (used!) and 3 made it do really crazy things, but two made it just keep resetting. Then I checked all the daughterboard roms, all seemed fine. I swapped out all 4 of the smaller proms, no difference.
So, I ordered more ribbon cables. I put a BRAND NEW ribbon cable on it, won't boot. Put the z80 back in, works fine as a Pac Man.
Started thinking maybe the daughterboard draws more power and maybe I've got power issues (I had already cleaned the edge connector, etc.)...
So I checked the fuses. I found one of the 7V fuses looked perfectly fine, but was at least partially blown (tested open with the meter).
The damn game would WORK without the fuse if it was a Pac-Man, but wouldn't work if it was a Ms. Pac Man because of the extra circuitry. Popped a new fuse in, works perfect.
In other words, NEVER ASSUME the power works just because the board is running. LOL.
So, I've got a Ms. Pac man that I've been having issues with. The board works fine as a pacman, but when you add the daughtercard and ribbon cable, it won't boot (keeps resetting).
So, I tried 5 different ribbon cables (used!) and 3 made it do really crazy things, but two made it just keep resetting. Then I checked all the daughterboard roms, all seemed fine. I swapped out all 4 of the smaller proms, no difference.
So, I ordered more ribbon cables. I put a BRAND NEW ribbon cable on it, won't boot. Put the z80 back in, works fine as a Pac Man.
Started thinking maybe the daughterboard draws more power and maybe I've got power issues (I had already cleaned the edge connector, etc.)...
So I checked the fuses. I found one of the 7V fuses looked perfectly fine, but was at least partially blown (tested open with the meter).
The damn game would WORK without the fuse if it was a Pac-Man, but wouldn't work if it was a Ms. Pac Man because of the extra circuitry. Popped a new fuse in, works perfect.
In other words, NEVER ASSUME the power works just because the board is running. LOL.