Pac 4 in 1 problem

don1400

Member
Joined
Apr 9, 2005
Messages
459
Reaction score
11
Location
Green Bay, Wisconsin
Hello,
Recently I wired up Jasons 4 in 1 Pac and I am having some problems perhaps someone here could offer a suggestion or two. First, the board ran absolutely 100% with regular Pac ROMs. After wiring the board and burning the 4 in 1 ROMS two problems exist. Game resets frequently on menu screen and either Pacman game and immediately resets as soon as I start either Ms Pacman game. I burned two sets of ROMS and the problem was consistant. I checked Mowerman's site and saw that chip 8B could cause frequent resets, after changing that chip there was no change in problem. Checked my wiring and all is correct. Sockets for daughter boards, Z80 and the 2 sockets for the hack have been replaced. Put Pac ROMS back in and board still runs perfect.
Anyone have any thoughts?
Thanks,
Rich
 
Pacman 4 in 1

Just going out on a limb, but what speed chips did you use?

I looked up the data sheets for the brand chips I have and the 27C020 is rated for 55ns, the 27128 is rated for 250ns, I'm using a Z80A CPU. I don't think the speed of the chips is the problem, I've built 3 other 4 in 1's using the same batch of chips and didn't have any problems till now. I really find it interesting that I can play Pac and fast Pac with no problem other than the resets but I cannot play either Ms Pac game, as soon as I hit start the game maze comes up and immediately resets to menu every time.
Rich
 
Measure your +5 at one of the eproms and see what you have. I have seen pac boards run great as pac but wont run mspac. Flaky power can be a cause of this. I have also seen a bad 2114 ram where the board played as a pac fine but as a mspac it would boot but reset when a game is started. Actually, I have seen that exact thing on two different occasions. Replaced the ram and mspac ran great.
So, check your voltage and swap out the 2114 one at a time and see if the issue clears up. Sorry, best help I can give you without the board in front of me.
 
Back
Top Bottom