Ms Pac RED Ghost problem

monty_a900

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Donor 2011, 2013
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Hope you're having a good Saturday ;-)

Anyway, I'm having some problems with a Ms Pacman board. Everything seems to work fine, except the red ghost only moves left & right. The rest of the ghosts are fine.

Using original PS (getting a good 5V on the EPROMS), repaired the edge connector. Tested the board with and without the daugter board - same problems.

Any help is appreciated?
 
Haven't seen that one before...

Do all the other ghosts move normally or do they jerk as the move? If they jerk as they move then replace the 74S89 RAM
 
Yes, all the other ghosts move fine. I had tried adding a switching PSU, and that made them all "twitch", changing the voltage from 4.5 to 6 improved things, but still not right (RED ghost and some of the others behaved oddly). I went back with the original power supply and returned back to the red ghost not moving up or down, everything else fine (as it was before I tried the switcher in the first place)

Actually, I *was* getting a "1" on bootup sometimes, seems to have gone now. I know that relates to a RAM issue?
 
I think a "1" on boot up denotes a fail in the 6F chip?? You have a spare 6F to throw on there to test?
 
I never ran across that issue before either. I guess the rom had to fail in a certain way for the other ghosts to run fun and the one not. Glad it was an easy fix.
 
Eh High Five!!! (Borat) :)
Good to hear that worked out for you. Never seen that one either, but the "1" on boot up was a good bet the 6F was on the fritz......
 
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