Ms Pac giving me a blue sac (help needed)

vintagegamer

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I acquired a Ms Pac some time ago that played blind, and needed a chassis and a tube. Oryk hooked me up with a tube, and Peale helped me with a chassis. I hooked everything up last night, and, of course as my luck likes to go, the game now does not play. I have checked the edge connector (and cleaned it), checked all of the fuses in the brick with a DMM and they are all good, reseated chips, and the best I can get now is the screen powers up with a bunch of garbage, and it makes a sound that is similar to Atari 2600's space invaders (*chip* *chip* *chip* *chip*), almost like a marching sound. I disconnected the monitor to see if I could get it to play blind again, and of course it won't.

I have a Ms Pac switching power supply lying around, should I try swapping that in to see if maybe it's a power issue? It got late on me last night after I hooked up the monitor, so I didn't get time to check out the schematics to test for power ranges going to the main PCB. I also don't have an extra Z80 lying around to put on the board to see if it's the Ms Pac daughter board.

Any chance this could be related to whatever that filter board issue is that people talk about?

Nothing like a game that plays blind, and then you get it to "see", and then it don't work.. That's how alcoholics are born...
 
Think I may have found a lead:

http://home.comcast.net/~jpittman2/pacman/pactrb1.pdf

Before I was getting the garbage on the screen, I kept getting a msg in test mode that would read BAD C RAM 0 which would flicker and change to BAD W RAM 0. Those are listed on the doc at the attached link. After a while I wasn't getting those messages anymore, just a black screen. So, I'll have to see if those locations are chips that can be reseated and go from there.
 
Or keep down the road you're going and save yourself a ton of money.

I know I'm close with it. The thing that's really trippin' my trigger is it was PLAYING BLIND not more than 3 mos ago! I moved it into the lineup after I got my replacement tube from Oryk, and was simply awaiting a monitor chassis. I get the chassis, pop the thing in and.......... the game decides to puke. I know it's a woman but come ON!
 
haha, that's how these bastards go.

I benchtested my burgertime guts and all was well, then I put it in the cab after restore and it decided to glitch. I was just as pissed / let down, but it made me re-solder sketchy joints, and polish chip pins. Problem went away, and now I trust the board better since I did all that. Same will be for you.
 
haha, that's how these bastards go.

I benchtested my burgertime guts and all was well, then I put it in the cab after restore and it decided to glitch. I was just as pissed / let down, but it made me re-solder sketchy joints, and polish chip pins. Problem went away, and now I trust the board better since I did all that. Same will be for you.

The thing I don't get is if you saw the condition of this game, it looks like it was in the basement at the Addams Family house. From there she rode home on her back, and then got pushed into my garage when it was only like 30 degrees outside. It worked at the seller's place, and it continued to work at my place after all that. And now, when I get the vid back up to par, the board decides to act up. I swear these things are alive.
 
MOTHER OF GOD PLEASE HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Last night I spent 3 hours removing and reseating chips, replacing the Z80, doing every other tweak I could possibly think of, and all I could get was garbage on the screen (have a pic will post shortly).

First thing this morning I finally found the Happ Controls Ms Pac switcher I knew I had lying around, so I figured I'd bypass the original PS altogether and integrate the switcher. I checked the 2 wires going to the monitor and I had 125V, so I knew I was all set.....

Hooked up the switcher, but the piece in that goes between the edge connector and the board, and fired her up. For about 1.5 secs I saw the green light on the switching supply, then suddenly a brief blue glow came from the........... POWER BRICK. I checked the fuses with my DMM and all had blown but the 2 slow blows on the left side. WHAT. IN. THE. FUCK???!! This Ms Pac has had everything done but a hysterectomy (rebuilt monitor, tube replaced, chips reseated, an attempt at a switcher), and now I'm blowing fuses???!! That's the first time that happened.

Before I go and get my sledgehammer, can anyone tell me what would have caused this? And where do I go from here? FUCK.

Oh and in the meantime, while working on this one last night, I look over at Ms Pac #1 which was on and has been working flawlessly. It had a couple icons on the screen and nothing else.. I turned it off and back on and.... I get the blinking 0 now. I swear they're conspiring against me!!
 
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I flat out have no solution for your problem, but I thought it was more important to let you know you should immediately trademark your thread name and promptly start selling t-shirts on the Jersey Shore with that name.
 
O.K., the little finger board, are you sure you didn't install that backwards between the pcb and the harness?

as far as i can tell you can only put it in one way bc both the finger board and edge connector have a notch in them. Further info is the 125v comes from a wht and blk wire off the middle of the 2 tall things in the middle of the power brick, rigged by prior owner.
 
went back and checked and all is right w the switcher's wiring. Anyone have any idea what could have made it blow 4 fuses? she's gone from suck to blow(S fuses).

Im no expert and this may be generic, but possibly something along your path lost all resistance and you are getting a straight shot of amps through the fuses. Maybe something in a connection is touching or frayed and is shorting out. Wrong gauge wiring? Just thinking outside the box at this point.
 
went back and checked and all is right w the switcher's wiring. Anyone have any idea what could have made it blow 4 fuses? she's gone from suck to blow(S fuses).


Yeah, an edge connector plugged in backwards. Also if you plug the EC in with the machine powered up that will sometimes happen if you dont have the fingers lined up right when you push it on. Typically a pcb problem will only blow 2 of the 4 fuses.
Your welcome to send that board over anytime and I will check it out for you.
 
Yeah, an edge connector plugged in backwards. Also if you plug the EC in with the machine powered up that will sometimes happen if you dont have the fingers lined up right when you push it on. Typically a pcb problem will only blow 2 of the 4 fuses.
Your welcome to send that board over anytime and I will check it out for you.

Just to rule another possibility out, I went ahead and hooked up the edge connector and the switcher in reverse of what I'd done last time, to make sure that there wasn't something wrong on the finger board. The result was that the 4 fuses blew again, just as they had when I'd set up the finger board the opposite way. Long story short, I guess this means I won't be able to use the switcher adapter to bypass any possible power brick issues. I totally don't get why it wouldn't work, but it's not.

When replacing the fuses again, and pulling the switcher supply out of the equation, I'm back to everything powering up OK, and having a board that displays color, non-moving garbage (I have the troubleshooting guide, and of course it says about 5-7 diff chips can cause this so, I'll have to go through that list now).

In the meantime I'm going to do a fuse holder swap (one of the 1 amp holders is loose).

This was my $50 Ms Pac find, and I think I'm learning to stay away from 50 dollar games going forward. :(
 
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I replaced the fuse block yest and no change, still just color garbage on screen so i guess it's pcb troubleshooting time. Sigh.
 
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