(Topic ID: 74111)

Mr. & Mrs. Pac-Man Pinball - underside of playfield photos/switch matrix

By thedefog

7 years ago

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  • 29 posts
  • 7 Pinsiders participating
  • Latest reply 2 years ago by pmpr13
  • Topic is favorited by 2 Pinsiders


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#1 7 years ago

Hey everyone,

I was wondering if someone had a photo set of the underside of the playfield for Mr. & Mrs. Pac-Man. I'm restoring one for my brother & his fam for x-mas, nearly done, but have a few unresolved issues I need to work out and photos of a working one would be a huge help and time saver.


#2 7 years ago

What do you need to see specifically?

#3 7 years ago

The issues I'm working on are switch-matrix related and switch wiring. The A in the left side PAC Targets, the Top Left Saucer switch wiring, and the middle upper drop target have been problematic and intermittent. Some other nearby switches also occasionally are intermittent.

Replaced diodes on those switches, cleaned switches, they tested in continuity. Traced the row wire (Brown and whie striped) between switches and back to the MPU, connection is good there as well as components on the MPU. Perhaps a frayed wire somewhere....

The real head scratcher is that a number of the switches have caps on them, whereas the schematic does not say they should have caps. The upper left saucer switch had one, the middle upper drop target did not, the A target did too. I followed the schematics and removed them on the saucer. Now I cannot get any of those three to activate at all. Re-added the caps, but cannot get them to work again. My guess is a frayed wire, but I just want to be sure I have my switches wired properly before replacing wiring.

There were a number of repairs done previously that were questionable, and having detailed photos of the entire underside would be pretty helpful to compare with. I have no issue going through the schematics, but I'm up against the clock now with getting this finished by x-mas.

#4 7 years ago

Unless the caps are shorted they really shouldn't be an issue whether on the prints or not (as long as installed correctly). I have a semi populated playfield in the warehouse, if no one else gets you what you need I will swing by there on the way home and snap some pictures.

#5 7 years ago

Hey Marc, I really appreciate that, but don't go out of your way or anything for it. I'm sure someone here has them already or can snap some on a home machine real quick.

Here is the switch matrix with my issues listed:


#6 7 years ago

The caps are in the schematic. These are debouncing caps and they extend the amount of time a switch registers as closed. They are not on all the switches. They are listed on p 3 of the PDF in this file:


They are .05uf/12v green disc caps. I replace them with these:


They are known to go bad. Not uncommon for them to be cut by ops that didn't want to replace them. If one is bad best to replace them all - there's 10 in total on the playfield switches.


#7 7 years ago
Quoted from viperrwk:

They are known to go bad. Not uncommon for them to be cut by ops that didn't want to replace them. If one is bad best to replace them all - there's 10 in total on the playfield switches.

Mine were cut out on a few places. That pretty much explains everything then, as I soldered them back in since it looked like they broke loose from vibration. I've never had a disc cap fail anywhere except on a power amp from heat, so I wouldn't have even suspected it. This is probably the root of all my issues. I'm just going to stick to the schematics, remove them from switches that shouldn't, and replace all with poly caps I have in abundance. Thanks.

This was the era of debouncing via cap, not software timing... Sometimes I forget about things like this.

#8 7 years ago

I checked out all of the caps installed on the machine last night. There were definitely a few of them shorted, and one of them had completely fallen apart. I replaced all 10 of them where they should go according to the schematic with .047uf poly caps at 25v, and removed those that shouldn't have been there. Unfortunately, it just made matters worse. Adding the caps onto these switches kept most of them from triggering at all, sans 2 or 3. So something is still screwy with my matrix. When I removed all the debouncing caps, some of the switches came back, but now I've got a few others that are misbehaving.

Tonight I'm going to go through each and every switch, check diodes, continuity, point to point wiring and mark them off one by one, and clean up the solder mess on some of them. Once I am certain everything is working and adjusted properly, I'll move on to possible MPU issues.

Pictures would probably still be pretty useful if anyone has them handy.

#9 7 years ago

Started going through switches last night. Got the left 1/2 of the machine done. There were two diodes installed backwards on the two roll over switches on the left side, but from what I read it seems like the direction doesn't matter according to http://techniek.flipperwinkel.nl/ballyss/rep/index3.htm.

I'm just replacing all switch diodes everywhere at this point while checking continuity on the switch and on the wiring chains.

Edit: I misread "does" in that link. Diode direction certainly does matter. It's still early...

Post edited by thedefog : Misread

#10 7 years ago

I didn't read through the link but diode polarity most certainly matters in the switch matrix.

#11 7 years ago
Quoted from Marc:

I didn't read through the link but diode polarity most certainly matters in the switch matrix.

I read wrong. They say "does" not "doesn't". I figured that didn't make any sense with the send/return wiring. My brain doesn't really start working until I've been awake for a good 5+ hours.

#12 7 years ago

Well I'm back to the brown wire w white stripes issue again w the top left saucer, a letter target, top middle drop target, and the star rollover. Turned out I had resolder a wire going to the coin door that was stuck open in the test because I saw it was cut that caused issues.

#13 7 years ago

if you need any, i can post some pix, but mine isn't working at moment (disclaimer)

#14 7 years ago
Quoted from thedefog:

Well I'm back to the brown wire w white stripes issue again w the top left saucer, a letter target, top middle drop target, and the star rollover. Turned out I had resolder a wire going to the coin door that was stuck open in the test because I saw it was cut that caused issues.

and the issue is that they do not work at all or are suck on or???? do the other switches in that row (tilt, left cabinet button) work?

#15 7 years ago

I took apart all of the switches and cleaned them really well,desoldered everything and replaced diodes, also reseated the CPU connector. All is good again, and just in time for the x-mas present delivery for my brother and his family. Thanks for your help guys.

4 years later
#16 2 years ago

Sorry to resurrect such and old thread but I am having a very similar issue. In my case everything is working except for the upper left saucer (no ball detection), the 3 yellow drop targets near the upper left saucer (the left most scores, the right most scores, but the middle one fails to score) and the 'A' target in pacman doesn't score. Seems like similar to thedefog it's all stuff on the brown and white wire. Connectivity looks fine on what I know is on the wire and I tested the diodes I see and the flow seems to be in the correct direction. What else should I be testing. What on the door is on this wire? My door magnet doesnt seem to be working, is that related?

#17 2 years ago

A couple other things not working in addition to the above. The large tilt with ball and track, when the ball makes contact with the switch nothing happens. The coin door coil/magnet? doesn't seem to do anything (honestly not sure what exactly that's supposed to do). The tilt bob when making contact turns off a bunch of playfield lights but doesn't seem to light up tilt on the display, I'm not sure what the tilt bob is supposed to do in this era of game. The slam switch on the door and cabinet work fine but there is one on the playfield near the right flipper that does not work (does nothing when the contact is made).

I have also been trying to troubleshoot and noticed most of what's not working seems to be on the brown and white wire as mentioned in my earlier post and in the switch matrix diagram that you can see thedefog posted you can see on A4J2-14 it mentions a few thing I have mentioned but also mentions "TILT" and "LEFT CABINET BUTTON". Which TILT and LEFT CABINET BUTTON are they referring to here. There are lots of tilt mechanisms and I don't see any Left Cabinet button outside of the Left Flipper Cabinet Button which I see on the upper right portion of the diagram on A4J2-8.

Any help understanding what to fix here and/or the switch diagram and/or correct TILT behavior would be greatly appreciate.

#18 2 years ago

Referring to the schematic above, you have a problem with I6 and that wire goes back to j2-14 on the MPU so I would start there. Pull the mpu and check the connections on the bottom of the connector pins.

#19 2 years ago

Thanks for the help. Yup agreed it's I6 which is connected by a brown and white wire but that's also why I am asking what the TILT and Left Cabinet button it is referring to so I can check those switches / isolate them, although I am thinking that left cabinet button is probably a typo and it should really be the other slam switch that is not working as I can't find that anywhere on the diagram and it definitely has a brown and white wire on it. Also, I know it's not the MPU directly as it has an alltek in it and I also swapped for another known to be working with the same result. Any other thoughts or info? I am going to check the connector and connectivity again but I think it has to be something on one of the switches that I am missing.

#20 2 years ago

Any other ideas? It would be great to know even just what the behavior of the tilt bob and incline tilt are supposed to be.

1 week later
#21 2 years ago

So I know first hand now that something is wrong with the tilt as I was able to compare to a working system. But I still can't seem to find what is wrong on the line. I may just reach the nuclear point of replacing every diode and ceramic capacitor on the brown and white line and tilt but if anyone has something specific to try please feel free to chime in.

#22 2 years ago

Have you checked for continuity on that brown-white wire between the MPU board and the plumb bob tilt mechanism in the cabine?

Also, does the tilt switch on the playfield (next to the right flipper mechanism) work?

#23 2 years ago

So I don't see brown and white wire on the tilt bob, but I do see it on the play-field tilt and continuity test passes, although the tilt on the playfield, as well as everything else on the brown and white except for the coin door micro switch, does not work. I tired with a different coin door as well as disconnected coin door and no difference. The tilt in the cabinet basically dims lights / causes some light to light up and causes one of the player displaces to display some weird output. If I cut the diode on the inclined tilt then it has no reaction at all. This thing is driving me crazy as I feel like I am so close yet so far away any additional thought or help would be great. FYI I also cut the capacitor on the tilt just to make sure that wasn't shorting and causing odd behavior and it made no difference.

#24 2 years ago

The schematics say the cabinet tilts have a blue/orange wire and a red/green wire from the MPU board.

Sorry, there shouldn't be any brown/white wire on the cabinet tilts.
There is a brown/white wire at one of the coin chute switches according to the schematics.

Have a look at the two tilt boards here:
This is typical of Bally setup.
The white/black wire on the lower brass ring around the plumb bob comes from a diode off the back of the tilt ball roll cage where the red/green wires are.

#25 2 years ago

So I have a working machine right next to it so form a wiring perspective I am not seeing it. But there is a brown and white wire on the tilt switch on the underside of the play-field (consistent with the working machine next to it).

#26 2 years ago

"I6" is a brown-white wire to the playfield. BUT on the cabinet/coin door switch wiring harness, "I6" is a blue-orange wire.
The brown-white wire to the cabinet/coin door is on switch return "I1".

Post pictures of your tilt board so we can see what you're dealing with.

Click the diagram below to zoom in.


#27 2 years ago

Sorry for the delay. I can take a picture no problem and should be able to post one tonight or tomorrow. But I am still confused on how the brown and white line ultimately feeds into the tilt. I would love to get the tilt working but the most important thing to me is getting everything else working on the brown and white line.

#28 2 years ago

The I6 switch return line from the playfield is a brown-white wire.
The I6 switch return line from the cabinet is a blue-orange wire.

At the MPU board, I6 on the playfield (J2) and cabinet (J3) connectors is the same signal. It sounds like you have a short to ground somewhere in the switch matrix - this is a little symptomatic of the issue you're having when closing the tilt switch mechanism in the cabinet and lamps/display digits are affected.

I don't see any mention of you reporting what Switch Test mode is indicating. This is an important step in diagnosing your problem. So remove all balls from the game, make sure all drop targets are raised and go into switch test mode. Let us know what it's telling you.

1 month later
#29 2 years ago

So I know this is a bit old but, with your help, I finally figured out the problem. You were 100% correct, short to ground was the issue, the previous owner had taken the blue-orange wire and rather then screw it into the slide tilt had decided to screw it into the the ground screw on the cabinet. This is was cuasing the tilt behavior issues as well as all my issues on I6. Thanks so much for the help!

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