Pacman trouble

coinopjunkie

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I see on craigslist all the time stories of my machine worked fine before we move it and now it doesn't work I never believed it until I lost two games in one day from moving them.

I had a perfect working pacman until I moved it about 45 min in super high wind with no back on it. Upon powering up nothing completely dead except for of course the marquee. I first thought maybe I know a far stretch that the high wind blew the stickers off my proms and the uv from the sun erased them, so I swapped a known working set of chips into the board and put it into a factory mrs pacman cab and it blows the fuses. I should mention the first pacman cab is a conversion with the switching type power supply and the mrs pac man is all factory. I then put my dmm on d7 and d8 as well as d4 they all show continuity on the bad board and on the good board there is no continuity so I would assume they need to be changed ? the next question is what are they d7 and d8 look like funky diodes is this a common part ? if anyone could tell me what I need to buy for these 3 parts I would appreciate it.

The other game that died in the same trip was a newer jamma setup and the power supply went bad is it common to have problems from moving machines? I have moved dozens with no problems and then two dead in one trip?
 
Uh oh...

When hooking a Pac up to a switching power supply you bypass the rectifier diods or you hook up wires after them.

Depending on how it was done you may have applied the AC power from the Ms Pac cab directly to the chips. If that is the case then the board will have massive chip damage.

Post pics of the modified board please.
 
that's one rough looking edge connector and soldering job..

yes, board is in bad shape if ac power went into the chips as channel stated.
 
You may want to look up Riptor here on KLOV...
If anyone can fix that mess, it's him...though I'm sure there are others, he seems to be the local expert on Pac boards.

Good luck :)
 
After having AC run through it I wouldn't want to put it on my bench. It could be simple... it could be a basket case. You just don't know at this point.
 
You may want to look up Riptor here on KLOV...
If anyone can fix that mess, it's him...though I'm sure there are others, he seems to be the local expert on Pac boards.

Good luck :)

+1

If not Riptor, then you could probably get the chips from him. You should plan on replacing many to all of em. :(

I would start with a dedicated power supply and a working cpu chip.
 
You can download the troubleshooting guides here:
http://pdf.textfiles.com/manuals/ARCADE/

Look under P for:
Pac-Man & Ms. Pac-Man - Troubleshooting Logic Board Part 1 [English]
Pac-Man & Ms. Pac-Man - Troubleshooting Logic Board Part 2 [English]

You'll find schematics there. You can take the part # for the diodes and look 'em up at http://www.nteinc.com to find the NTE cross reference.

RJ
 
Anyone happen to know what d7 and d8 are and where to get replacements.

I use standard 1N5402 for these.
Im not sure why people jump those diodes out when running a switcher. I just run the dc straight through the diodes and bump the PS up to compensate for the lose through the rectifier. Never had any issues doing it this way and you dont need to change anything on the pcb.
 
If I remember right, from the diodes the dc power goes to a 7805. I hope that is where your problem stopped.

I have another suggestion for you. I have a Galaxian and a Dig Dug PCB and I solder a connector to the points past the diodes and ground. I use a computer power connector, the type for cd, floppy, etc. drives for this. By doing this you can use a switcher with the connector and edge connector via the cab. I can post a pic latter if there is any interest.
 
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