Ms Pacman won't power on - power supply and fuse questions (2025)

My boss has an original Ms Pacman cabinet that won't power on. I've tinkered a bit with machines before but don't know a lot so I could use some input about what's going on with the wiring:

First obvious things I noticed:

1) Kill switch needs to be remounted
2) Some sketchy wire splices should be redone
3) It looks like a switching power supply was added, and theres a dangling connector from that power supply to the PCB near the edge connector
4) There's missing fuses - but if the switching power supply is being used are they needed?

My main questions surround 3 and 4 above -

-Where does this dangling connector need to go?
-Do I need to replace the missing fuses?

Any help is greatly appreciated!

great detailed post!

it's in the correct forum section!

all you gotta to do magically fix your problem is replace the fuse block with a new one, solder on wires, put in new fuses. 100% fixed.

thegleek said:

great detailed post!

it's in the correct forum section!

all you gotta to do magically fix your problem is replace the fuse block with a new one, solder on wires, put in new fuses. 100% fixed.

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Thanks for the reply! I figured the fuses were a red flag.

Any idea what's going on with this wire near the edge connector? It's not connected to anything, just draped over the board.

Jessikwa said:

Thanks for the reply! I figured the fuses were a red flag.

Any idea what's going on with this wire near the edge connector? It's not connected to anything, just draped over the board.

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yes, typical with pacman pcb's the +5vdc pushes too much power/voltage/heat/etc to the edge connector and burns it out. 75% of all pacman pcb's have additional wire or repair to this part.

thegleek said:

yes, typical with pacman pcb's the +5vdc pushes too much power/voltage/heat/etc to the edge connector and burns it out. 75% of all pacman pcb's have additional wire or repair to this part.

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I'm a bit confused - is it supposed to be connected to something? Touching the metal bit of the edge connector or something?

wugly said:

I assume that wire ties into the gnd on the switching power supply. We need a picture of what terminal it's connected to

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Doh yeah it runs back to the "gnd" terminal so that's makes sense (black wire below)

wugly said:

May I suggest not putting the fuses in that supply ac voltage to the edge connector of the board. I am not sure from what I can see but they might have put the DC in there. Won't hurt board if you put in DC but unsure what will happen I'd both get introduced there or what it will do to the switching power supply

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it'll probably nuke the power supply. the doubled voltage will be nerfed by the regulator on the board. (I plugged a JAMMA adapter in backwards and fed +12V into the +5V side and didn't kill anything LOL)

also those single wires off the power supply are insufficient. those Pac boards are long enough you'll lose power at the opposite end, like Atari. if the edge contacts are scorched, the proper fix is copper tape. but don't buy 1/4" like I did (which I'd intended on using it for JAMMA but needed it for Galaxian/Pac later), otherwise you wind up having to cut it in half to replace the 7V AC contacts. there are a number of these games still working with even the factory fuse holders (which should be replaced) so you shouldn't need the extra power supply at all. just do it right and it'll probably survive another 40 years.

if all of this is above your pay grade I understand. I'm sure you can summon someone nearby to help.

Hey guys - got some new fuses and holders ordered, but also couple more questions for you all after looking at the machine again:

I found a couple more dangly-wires, one of which is coming from the screen so that seems kind of important Any suggestions appreciated!

Oh then there's also this dangly-guy too - maybe supposed to be grounded to something?

Man you really need to download the manual and get familiar with this wiring this game needs.

Frist pic is you degauss wiring that needs to be connected to your chassis on the monitor. Most of the cabs came with a G07.

Second pic is most likely your marquee lighting.

Third pic is the monitor FG ground wire. Just attach it the the metal frame on your monitor.

Also pull the elec tape off your interconnect switch by your back door. You can just pull the switch out and it will stay that way for testing when the back door is off. No need to tape it in the closed position.

Sorry, I did look at the manual but I didn't find this information.. I also have a pretty minimal working knowledge of these machines. I appreciate the responses!

I'm looking at the monitor chasis, but I'm not seeing anywhere that that wire may plug into? I'll keep hunting around for documentation on it.

Best guess is your third pic up top where it says AC IN. There are two pins that those degauss coil wire should go to.

Maybe post some pics of the monitor chassis labels so we can identify which Sharp Image this is.

You need to start by checking power. That interlock switch looks like it is not fully pressed in by the tape. Remove the tape and manual press in the switch. Some pull out to remain on, not sure if that is one of them or not, but it looks like one.

The empty fuse positions need to stay empty. They were pulled because of the switching power supply modification. If you put them in they will probably just instantly blow anyway.

Test the other fuses to make sure they are good.

Make sure power switch on top of cabinet is turned on.

See if you power supply red LED comes on.

Go from there.

You need to ultimately replace the fuse blocks but at this point just see if you're getting power or not.

The 3 pin connector in your hand goes to the marquee light and will not prevent the game from turning on.

It might be just as simple as the interlock switch.