LyonsArcade
Well-known member
Hi guys;
I've got a dedicated Super Pac-Man that I'm working on, and it has a strange issue. The character won't go left, or down. Right and up works great. If you switch the wiring around at the pcb, left and down on the joystick work if you hook them up to the up and right inputs, so I don't believe anything is wrong with the wiring or the joystick.
If you put the pcb into test mode, it says all roms, rams, and inputs are fine. Also, in test mode, all the directions work to change the 'sound' test. So it appears that there's actually nothing wrong with the 'input' of the board, only the 'output' of the video or whatever to make the character actually move to the left or down. It's like the game is getting the correct signal from the joystick, but just won't actually make the character move that direction.
When the inputs go in the board, they run through a set of resistors and then into one of those large Super Pac custom chips. There's another custom chip that handles the dipswitches that is the same number, I switched those two around and there's no change. I checked the sockets, and they check out fine. If you 'ohm' the resistance from the pin on the pcb through to the pin on the custom chip that it connects to, you get 2.2k which is the value of the resistor those lines run through; all the 8 direction inputs ohm out the same all the way to the custom chip (I checked player 2 even though it doesn't wire up in the upright). None of the directions are shorted to each other either.
Does anybody have any idea what I can check next? I'm pretty sure it isn't an input problem, but something after it goes through that custom chip. I've cleaned and reseated all the custom chips on the board.
Any help is appreciated!
I've got a dedicated Super Pac-Man that I'm working on, and it has a strange issue. The character won't go left, or down. Right and up works great. If you switch the wiring around at the pcb, left and down on the joystick work if you hook them up to the up and right inputs, so I don't believe anything is wrong with the wiring or the joystick.
If you put the pcb into test mode, it says all roms, rams, and inputs are fine. Also, in test mode, all the directions work to change the 'sound' test. So it appears that there's actually nothing wrong with the 'input' of the board, only the 'output' of the video or whatever to make the character actually move to the left or down. It's like the game is getting the correct signal from the joystick, but just won't actually make the character move that direction.
When the inputs go in the board, they run through a set of resistors and then into one of those large Super Pac custom chips. There's another custom chip that handles the dipswitches that is the same number, I switched those two around and there's no change. I checked the sockets, and they check out fine. If you 'ohm' the resistance from the pin on the pcb through to the pin on the custom chip that it connects to, you get 2.2k which is the value of the resistor those lines run through; all the 8 direction inputs ohm out the same all the way to the custom chip (I checked player 2 even though it doesn't wire up in the upright). None of the directions are shorted to each other either.
Does anybody have any idea what I can check next? I'm pretty sure it isn't an input problem, but something after it goes through that custom chip. I've cleaned and reseated all the custom chips on the board.
Any help is appreciated!