I broke my Ms. Pac-Man

TheMaze

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I picked up a Ms Pac-Man a few days ago, and at the time it was in working condition (though needs a cap kit in the monitor).

So, I'm slowly trying to clean the machine up, as it has 30 years worth of filth in it. Today I took out the PCBs, cleaned them up with some alcohol and a paint brush, cleaned the edge connector, also removed the "fast" pad bridge the manual mentions, and cleaned the metal "cage" for them. Reassemble, and the problems begin:

Problem 1: No sound, but get amp hum. Game plays fine.
Re-seated the edge connector and works. Not convinced this actually fixed the issue, but I guess I'll run with it as it is working for now.

Problem 2: Game resets a bit into playing/doesn't boot
First, the game didn't boot (would cover the screen with the characters as part of the self test, then reset shortly after). Pressed down on all the socketed chips and it now boots and starts play, but seems to reset every little bit

Problem 3: Audio hum (this one existed before I started)
How much audio hum is expected on a Pac? This one sound like a cheap amplifier - are my expectations too high, or will new caps fix this

Does anyone have any thoughts on the above problems? I suspect my next step will be to actually lift the socketed chips and re-insert, rather than just pushing down.
 
Check to make sure none of the 4 fuses in a row are blown down in the bottom, sometimes Pac-man will boot up even with one of those fuses blown, but will reset, etc.

After that, I'd do what you said, take each chip out, clean it, reinsert it in the socket. You need to clean the pins in the edge connector to the board too, they get tarnished over the years and don't make good contact causing all kinds of problems.

Good luck!
 
Check for heat in the edge connector..
A warm connector to the touch indicates resistance between the connector and the board.
It might be time for a New edge connector.
30 years of heat and cold cycles might have weaken the edge connector pins enough to give you a poor connection issues..
 
OK, so I pulled the board and pushed on the chips with it on a flat surface (as opposed to in the cab). I could hear a lot of them move when I did this, and the good news is the game powers up now and seems to work. I still have the audio hum, but I had that when I started, so that's nothing new (does anyone know if that's normal on a Pac?)

Speaking of audio, I have what seems to be a new problem. One of the audio channels (plays the intro music, the intermission music, and I think the eating of power pills) sounds a bit scratchy (videos to follow). Any thoughts on what could cause this?

Also, I'm not sure if this is actually a problem, but the volume on this unit is VERY loud - I have the volume down almost all the way to have it at an acceptable level - turning it up all the way is ear-splitting. Is that expected?
 
Speaking of audio, I have what seems to be a new problem. One of the audio channels (plays the intro music, the intermission music, and I think the eating of power pills) sounds a bit scratchy (videos to follow). Any thoughts on what could cause this?

Also, I'm not sure if this is actually a problem, but the volume on this unit is VERY loud - I have the volume down almost all the way to have it at an acceptable level - turning it up all the way is ear-splitting. Is that expected?

Alpha-Tron,
I think this is what he is talking about with the audio channel, the intermission music and eathing of power pills.

Maze,
the problem is most likely BEFORE the amp but check the amp to be sure beond a doubt. Since you can not adjust the sound you probably have some kind of cap. problem. If the amp is good then I would look at caps and any other sound producing or processing, espicall it was working and now not.

Since you went through the troubble to clean, why not bullet proof. New caps, new dual wipe sockets, new resistor packs<a big + if you have the flat blue/green resistors> It is more work but probably won't need to be done again.

EDIT:
Could also be the volume pot is bad after getting wet.
 
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PAC man only has one speaker..

Are you saying that the static you hear is not the same through out the whole game and just in parts?

Correct. For instance, I only hear it on the intro music, the intermission music, etc.

kb0jjn is correct, I realize Ms. Pac-Man is mono - I'm talking one of the effects channels. To clarify, I can adjust the sound volume, I was commenting on being surprised how loud the audio was though, and inquiring if it is normal (basically, on a scale of 1-10, I'd say 0 is no audio, 1 is quiet, 2 is acceptable, 3 is loud, and 4-10 are ear-splitting)

I do plan on re-capping, just haven't gotten the parts list together yet and ordered parts. I suppose I should probably just give up troubleshooting for now and see if the problems magically vanish upon re-capping.

Any chance someone has a cap list handy for a Ms Pac and/or a ECC-20380 monitor?
 
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I picked up a Ms Pac-Man a few days ago, and at the time it was in working condition (though needs a cap kit in the monitor).

So, I'm slowly trying to clean the machine up, as it has 30 years worth of filth in it. Today I took out the PCBs, cleaned them up with some alcohol and a paint brush, cleaned the edge connector, also removed the "fast" pad bridge the manual mentions, and cleaned the metal "cage" for them. Reassemble, and the problems begin:

Problem 1: No sound, but get amp hum. Game plays fine.
Re-seated the edge connector and works. Not convinced this actually fixed the issue, but I guess I'll run with it as it is working for now.

Problem 2: Game resets a bit into playing/doesn't boot
First, the game didn't boot (would cover the screen with the characters as part of the self test, then reset shortly after). Pressed down on all the socketed chips and it now boots and starts play, but seems to reset every little bit

Problem 3: Audio hum (this one existed before I started)
How much audio hum is expected on a Pac? This one sound like a cheap amplifier - are my expectations too high, or will new caps fix this

Does anyone have any thoughts on the above problems? I suspect my next step will be to actually lift the socketed chips and re-insert, rather than just pushing down.

Do yourself a favor and replace the edge connector and fuse blocks if they are original. They will give you a lot of trouble if they are.
 
Do yourself a favor and replace the edge connector and fuse blocks if they are original. They will give you a lot of trouble if they are.

As far as I know it's all original (it has enough dirt at least...) - how does one replace the edge connector - it's part of the PCB. Also I have the filter board in mine still.

I assume you know this website resource..

http://lawnmowerman.rotheblog.com/

While I do not have a capkit list off hand if you need a axel capkit.

http://www.twistywristarcade.com/kits/17-pacman-mspac-pcb-capacitor-kit.html

I've seen lawnmowerman's site - there's actually something under sound there that mentions distorted intro music and the resolution is replacing 1L - I'll likely replace it and hope for the best.

Re: the cap kit, I'm going to just end up ordering from digikey/mouser, as I need to get some other stuff, and it's cheaper, so I was hoping for more of a parts list. Thanks though.
 
As far as I know it's all original (it has enough dirt at least...) - how does one replace the edge connector - it's part of the PCB. Also I have the filter board in mine still.

There are two halves to the edge connector. The PCB half, and the harness half. I was referring to the harness part.

The pins get weak and don't make very good contact. So replacing it, gives you much better contact, which cuts down on a lot of problems (such as Random Reboots).
 
No sound, you probably have a bad sound prom or socket. They are in location 1M and 3M. Static or distorted signs are also symptoms of bad prom or sockets. Alot of times its just socket connection problem and reseatting the prom takes care of it. Although in that case I will usually replace the socket anyways with a dual wipe to avoid the issue again later.
 
No sound, you probably have a bad sound prom or socket. They are in location 1M and 3M. Static or distorted signs are also symptoms of bad prom or sockets. Alot of times its just socket connection problem and reseatting the prom takes care of it. Although in that case I will usually replace the socket anyways with a dual wipe to avoid the issue again later.

Thanks - when I pull the board to re-cap it, I'll pay extra attention to those tockets. I also need to burn a normal 6F chip (as mine currently has a speed-up in it).

Regarding the fuse holders, mine has little plastic twist-in "cartridges", however the manual shows exposed "snap-in" fuse holders -which is the bad type? My Ms Pac has sticker side-art, so I suspect it was a late production unit.

Also a bit of an odd question, but the manual and other paperwork is still stapled shut (never opened) in the plastic bag inside the cab - are sealed manuals considered valuable at all?
 
Ah yes, its a late production model. I meant to mention that since you had said it had a pcb cage.
Sorry, the pac and mspac manuals are very plentiful and really not worth much more in mint condition. I would say around $20-$30 is about what you might be able to get for it.
 
Per the schematic, the Ms Pac has the following caps (all are axle lead):
Mainboard
C5 10uF 25V
C6 470uF 16V
C7 10000uF 10V
C8 10000uF 10V
C10 10uF 25V
C29 2200uF 25V
C48 4.7uF 10V
C51 330uF 10V

Daughterboard
C1 10uF 25V
C2 10uF 25V

I'll post part numbers once I order them from Digikey/Mouser

Should I also change the filter caps in the PS at the bottom? Do they typically cause an issue? I imagine they are several dollars each, and don't want to change them if it's pointless.
Also the fluorescent light is out in this. I need to find another tube to swap to try it - if that doesn't fix it, is there any way to tell if it's the starter or the ballast?
 
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I need to find another tube to swap to try it - if that doesn't fix it, is there any way to tell if it's the starter or the ballast?

I would not recommend just swapping in another fluorescent tube in there in an attempt to fix it. You might get lucky, but you might immediately blow the new tube.

My recommendation would be to buy a new starter ($1 at a hardware store) and test the ballast with a multimeter. Bob Roberts has some info on testing a ballast on his website here:

http://www.therealbobroberts.net/fixture.html

With a new starter and a tested good ballast, then you can put in a new fluorescent light tube.
 
I would not recommend just swapping in another fluorescent tube in there in an attempt to fix it. You might get lucky, but you might immediately blow the new tube.

My recommendation would be to buy a new starter ($1 at a hardware store) and test the ballast with a multimeter. Bob Roberts has some info on testing a ballast on his website here:

http://www.therealbobroberts.net/fixture.html

With a new starter and a tested good ballast, then you can put in a new fluorescent light tube.

+1 to this. I blasted 3 bulbs before I realized the ballast was bad. Test the starter and bulb in another cab first. If they both work, then the ballast is bad.
 
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