Ms. Pac won't boot/garbage screen (pic)

pomme

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Hey guys.

Picked up a Ms. Pac that isn't working. When I plug it in (previous owner has bypassed the power switch) I immediately get a garbage screen (non-moving) and that's it. I also have a loud buzz in the speaker.

Here's what it looks like every time:



I've cleaned the edge connector and re-seated the ROMs. I've also bypassed the daughter board and am getting the exact same result.

Found another thread that suggested replacing the fuse block right away. I've done that and am still getting the same thing.

I am no whizz at troubleshooting boards. Has anyone seen this same screen? It doesn't match anything I am seeing on the troubleshooting screenshot gallery. Any help getting me pointed in the right direction would be appreciated.
 
Hey guys.

Picked up a Ms. Pac that isn't working. When I plug it in (previous owner has bypassed the power switch) I immediately get a garbage screen (non-moving) and that's it. I also have a loud buzz in the speaker.

Here's what it looks like every time:



I've cleaned the edge connector and re-seated the ROMs. I've also bypassed the daughter board and am getting the exact same result.

Found another thread that suggested replacing the fuse block right away. I've done that and am still getting the same thing.

I am no whizz at troubleshooting boards. Has anyone seen this same screen? It doesn't match anything I am seeing on the troubleshooting screenshot gallery. Any help getting me pointed in the right direction would be appreciated.

it is trying to process code and is hung up. Try to re seat the rom chips, verify if possible. Verify proper voltage on the +5.

It is hung up on the ram Rom initial test.
 
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Verify that the traces between the CPU and the ROMs are good. Sometimes when removing/replacing sockets the traces or the plated thru holes get damaged.

RJ
 
^^ This. I bet you that Z80 is donezo. Oh, and remove the filter PCB if you havent done so already.
 
Check eproms/sockets in row 6, Z80 and sync bus card for starters. Could also be a bad 2114 ram.
Those red lines at the bottom of the screen are likely a whole different problem but you can deal with that after you get it booting.
 
Those red lines at the bottom of the screen are likely a whole different problem but you can deal with that after you get it booting.

Yeah I noticed when i flipped the dip switch to flip the monitor those stayed in the same place while the rest of the garbage flipped.. be on the lookout for that thread :)
 
Yeah I noticed when i flipped the dip switch to flip the monitor those stayed in the same place while the rest of the garbage flipped.. be on the lookout for that thread :)

Where is this dip switch, on the monitor? The game board has no dip switch to flip screen.
 
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