Ms Pacman Restarting/Glitching

Slam_Bradley

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I picked up a Ms Pac cocktail from a fellow KLOV'r Tuesday. The night I brought it home, the machine worked well aside from it rebooting once within the span of about 3 hours (happened right after a level was cleared).

Then came Thanksgiving day and I plugged the machine up along with another machine for my visiting family to play. It looked like it started to come up as normal but then the screen went black and the number "2" and what looks like a white ghost with the letter "M" on it in the upper-right portion of the display. So, I unplugged it and then gently pressed on all the chips on the PCB. Plugged it back in, same thing. Turned it off again.. peered inside and scratched my head a while. Plugged it back in again. The game came up again! A couple of people played the game about an hour and it reset once but the game came back up.

About an hour later after everyone left, I got to play the machine some before turning it off. It resets on me before I even clear the first board, and goes right back to the black screen with the 2 and the white ghost. Today I've been in a bit of a turkey coma, so I've yet to plug it back up again much less break out the multimeter and start checking voltages. I just wanted to run this by you guys to see if someone recognizes this as something common. I'm thinking either a power issue or PCB issue.

Everything seems to be original aside from the nice Wells Gardner replacement monitor that was thrown in. Same old power supply, etc.
 
I'm going to type this the most eloquently I can, cause I'm going to just add it to my site next.

Pac-Man and Ms. Pac-Man use the same main board, each take AC voltages from a fuse block connected to the multi-tap transformer. this transformer outputs 7V and 14V, which are rectified at the main board to +5V and +12V DC.

the big problem is the original brass (thanks Riptor) fuse holders will rust or corrode from being about 34-36 years old. the byproduct of this will result in the AC power not getting supplied from the transformer to the game board optimally. the edge connector in particular is prone to burning up from this condition, because this lost power creates resistance, which creates heat. (same exact concept with a JAMMA edge) the rectification hardware probably has requirements as well which contribute to the burning.

so how do you fix it? you can start with replacing the fuse holders. I've used this 4 fuse holder block from Marco Specialties, http://www.marcospecialties.com/pinball-parts/FHSM4 -- the nice part is it's shaped exactly the same and even has the same mounting holes. swapping the wiring over is a little more delicate of a process. make sure you only swap over a wire at a time, so you don't mix them up. solder might not stick to the copper wiring very well, some have suggested rubbing alcohol and scotch brite to clean them up; I've used sandpaper. then you just hook the wires into the fuse holder holes and then add solder. you can alternatively tin the wires with solder first to get it to stick, then attach to the holders.

if you still have problems with low voltage to the chips or the game resetting, you may need to rebuild the power section on the main board. this is also suggested if you have the hum bar condition.

since a lot of these game boards have been serviced by other people in the past (the 80s, 90s, 2000s, whenever) it's encouraged that you remove all socketed chips and ensure that the component legs are straight. Midway used single wipe sockets on these boards, and if the legs are inserted crooked or for whatever reason bent out of the socket, a myriad of issues can transpire due to poor connections.

if your edge connector was burned up, you will need to repair it with copper tape. or you can resort to one of the usual operator hacks where you solder wires to the board or something.

if you need additional help feel free to contact me.
 
Thanks for all this good info, Mecha. I seem to have isolated the issue to the ribbon cable to the daughter board. Pressing on each end of it made the game display more garbled graphics the first attempt, then the game worked good for 2+ hours with no reset after the 2nd attempt!
 
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oh good call. if you pop the CPU off the aux board and plug it in where the ribbon cable is installed now and have the game working solid, then yes, totally the ribbon all day long. do make note of where the notches face, so you don't plug the CPU in backwards.

you should have Pac-Man with a solid yellow Ms. Pac if it works this way.
 
Thanks guys. My girlfriend and I played it last night a while hasn't flaked out again since the last time, but I am going to go ahead and order replacements for the cable and fuse holders. After the game warms up a while, I get a small but noticeable pulsing "wave" on the right side of the screen that I suspect is the beginning of a "hum bar" http://www.twobits.com/Humbar/
 
Thanks guys. My girlfriend and I played it last night a while hasn't flaked out again since the last time, but I am going to go ahead and order replacements for the cable and fuse holders. After the game warms up a while, I get a small but noticeable pulsing "wave" on the right side of the screen that I suspect is the beginning of a "hum bar" http://www.twobits.com/Humbar/

thats AC related usually and could be the any connections which would include edge connector, fuse holders, etc. if you need parts i have all of them in stock and dual wipe ic sockets and ribbon cables.
 
Rising this from the grave to update..

After getting the new black fuse bricks in May, I finally got around to working on the machine a few weeks ago. Pulled the old fuses out, hit em with sandpaper, and set them in order off to the side, took good pics of old blocks from a few angles, snipped the wires as close to the old soldering at the fuse brick terminals as possible and replaced the fuse bricks. Then I stripped ends of the wires and soldered them back in place on the new, solder-prepped brick terminals.

Plugged it up with the edge connector off first. All good. Plugged up with PCB connected.. random sprites. Pushed on some chips and the ribbon cable connects again as I've done before seeing that.. turn it back on and it plays as it did but hasn't randomly reset yet.

I've still got a slight hum bar bend on the right. Hoping perhaps it's actually a worn out fuse at this point. These appear to be ancient fuses. I'll try swapping some tomorrow.
 
Rising this from the grave to update..

After getting the new black fuse bricks in May, I finally got around to working on the machine a few weeks ago. Pulled the old fuses out, hit em with sandpaper, and set them in order off to the side, took good pics of old blocks from a few angles, snipped the wires as close to the old soldering at the fuse brick terminals as possible and replaced the fuse bricks. Then I stripped ends of the wires and soldered them back in place on the new, solder-prepped brick terminals.

Plugged it up with the edge connector off first. All good. Plugged up with PCB connected.. random sprites. Pushed on some chips and the ribbon cable connects again as I've done before seeing that.. turn it back on and it plays as it did but hasn't randomly reset yet.

I've still got a slight hum bar bend on the right. Hoping perhaps it's actually a worn out fuse at this point. These appear to be ancient fuses. I'll try swapping some tomorrow.

Get some new fuses in there for sure, but I had the randomly resetting problem in my Ms. Pac too and it was just that the edge connector burnt the PCB edge too much. After fixing that, it's been perfect, so I think that should be your next step.

Fix the PCB with copper tape and replace the connector on the harness
 
Ever come back to a thread you posted in and find the solution to your current issue?

AC inputs on my Ms. Pac started acting up today, searched it up only to realize I never replaced the fuse blocks. Those have been ordered :D
 
Ever come back to a thread you posted in and find the solution to your current issue?

AC inputs on my Ms. Pac started acting up today, searched it up only to realize I never replaced the fuse blocks. Those have been ordered :D

Hey buddy! So weird, I was just thinking about you and this post the other day!

So, things improved but aren't "perfect" quite yet. I hope your machine is not a cocktail machine, because damn by back hurt leaning into mine to replace those fuse bricks haha I also replaced all of my fuses except 2 or 3 I didn't have on hand.

Mine played excellent for months with that slight humbar.. then one day after not playing it for a couple of months it reset on me. At this point I've got 2 things on my to-to list that I think I'll be doing next:

1. Replace the old power cable. It's 3-prong.. but it's ancient. Can't hurt to hack the ends off a PC power supply cable and slap that in instead.

2. Strongly considering converting to a modern switching power supply, but I want to do this is in the cleanest way possible. The machine always starts and plays properly since cleaning up the PCB edge and re-seating chips, but it still retains the behavior of "the longer it's on, the weirder things get" it seems. Edges of the maze start bending at high levels or the maze just straight up renders as the wrong color, etc. Plus of course.. to hell with that hum bar. Annoying things like that keep me from playing my games heh

Once I get it right I plan on periodically switching PCBs.. my original Pac with Ms-Pac add-on and another Pac with a highscore kit installed.
 
The cleanest way to convert it to a switcher would be with one of these.

http://www.arcadeshop.com/i/932/midway-power-supply-kit-3.htm

It would definitely fix your hum bar issues.

The screen curling however is a monitor issue. Either one of the pots need a small adjustment or some cap is starting to die and needs to be replaced.

Thanks! I see they are out of stock now, but I'll keep my eye out for one.

The monitor chassis was all reworked shortly before I bought it.. but if I do the first step and something still looks weird I'll try to adjust it out.
 
Ok, finally wrapping this thread up for any potential readers trouble-shooting.

I did NOT install the power switching supply kit per advice of a friend (he said to at least try to get all existing right first). Instead, my next step was that I finally got around to ordering a new edge connector to install. Re-pinned and re-wired that. Fired the machine up and it looks and plays great. No more hum-bar. No more resets yet.

Summary...

Background : All original cocktail machine with exception to "new" Wells Gardner monitor. PCB does has NOT been recapped and no sockets appear to have been replaced. PCB is running speed chip.

Problem : "Hum bar" effect, random resets and graphical glitching

Solution :
- Replaced ribbon cable from main Pac PCB to Ms Pac
- Replaced fuse bricks and all but 3 fuses (I did not have other types on hand. Cleaned the 3 old ones with sand paper)
- Cleaned PCB edge with fiberglass pencil and iso alcohol.
- Replaced edge connector.
 
Ok, finally wrapping this thread up for any potential readers trouble-shooting.

I did NOT install the power switching supply kit per advice of a friend (he said to at least try to get all existing right first). Instead, my next step was that I finally got around to ordering a new edge connector to install. Re-pinned and re-wired that. Fired the machine up and it looks and plays great. No more hum-bar. No more resets yet.

Summary...

Background : All original cocktail machine with exception to "new" Wells Gardner monitor. PCB does has NOT been recapped and no sockets appear to have been replaced. PCB is running speed chip.

Problem : "Hum bar" effect, random resets and graphical glitching

Solution :
- Replaced ribbon cable from main Pac PCB to Ms Pac
- Replaced fuse bricks and all but 3 fuses (I did not have other types on hand. Cleaned the 3 old ones with sand paper)
- Cleaned PCB edge with fiberglass pencil and iso alcohol.
- Replaced edge connector.

textbook fuse block/edge connector problem

1: your friend is a smart man
2: good on you for closing out a repair thread

have fun with her, Ms. Pac never gets old
 
1. That would be good ol' Arcade Buffet Man!
2. I can't stand when people ask questions, say "I got it!" and never detail wtf they did lol.

Thanks, bro! Love this game.
 
1. That would be good ol' Arcade Buffet Man!
2. I can't stand when people ask questions, say "I got it!" and never detail wtf they did lol.

Thanks, bro! Love this game.
A reply to an old thread. This is what I love about this site and all the knowledge, time, and effort people are willing to put forth to help each other out. I guess the biggest reason is we LOVE THESE GAMES… and are willing to spend the time and research necessary to keep them tip top.
I just picked up a Ms. Pac Man that played great on location, but stared resetting once I got her home. To be expected… we are dealing with 40 year old electronics.
Parts are still available… thank goodness.
And I'll get some new fuses and fuse blocks ordered.
 
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