Ms. Pac-Man Blank Screen

Silkyfresh

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This is what i was working with before..
http://img853.imageshack.us/img853/520/img00000005h.jpg

I assumed this was the VRAM addresser so i pulled it out cleaned the pins, put it back ran the machine and now all i get is a blank screen.

Pulled out the multimeter did a continuity test..found 1 blown fuse. replaced that, turned the game on same issue blank screen.

Turned it off, replaced the board with a brand new working board. Checked fuses everything good turned it on..same problem Blank screen. i do not see a neck glow and the game is not playing blind..not sure what to do now?

the name of the monitor i have is a Philips MV (A48ABK05X) hopefully that helps.
 
Since you say you swapped in a known working board and the game still didn't play blind I would suspect you have a voltage or even connectivity issue. I'd start by checking into these things. If the fuse block has not been replaced maybe do that too. The old ones sometimes cause issues over time.
 
You DID plug the main harness back into the PCB right? Believe it or not, I have worked a few boards, finished my work only to see a blank screen, only to realize I forgot to plug the PCB back in...DOH! If you did, time to check voltages.... the plug at the monitor should be getting 120vac, and find the ms pac manual online and check the voltages on your edge connector....
Also remember there is that plunger kill switch on the back of the machine that shuts the machine off if the back door is removed.....just sayin :)
 
You DID plug the main harness back into the PCB right? Believe it or not, I have worked a few boards, finished my work only to see a blank screen, only to realize I forgot to plug the PCB back in...DOH! If you did, time to check voltages.... the plug at the monitor should be getting 120vac, and find the ms pac manual online and check the voltages on your edge connector....
Also remember there is that plunger kill switch on the back of the machine that shuts the machine off if the back door is removed.....just sayin :)

Hm i plugged the main PCB connector in however there is another connector that plugged into the old board but doesn't plug on to the new board..i assumed it was for the speed chip?
 
Yeah, time to pull out the volt meter and start taking readings....also that is the tube #, not your chassis model. Take a pic of the chassis and post it if you are unsure the make.
 
Assuming you have 120v at the power input to your monitor (2 prong plug), your Wells Gardner 19K7xxx series monitor has shit the bed.

The white knobbed flybacks (which you have) are notoriously bad.

Your monitor chassis needs to be rebuilt with new caps, fly, and potentially a horizontal output transisor (HOT).

But first make sure that 120v is making it from the isolation transformer to the input plug on your monitor. I've seen several times that even bumping that cord can cause an intermittent connection.
 
Also, 'blank screen' could also be narrowed down even further - you say you tested the cabinet with a known working board.

Does the known working board coin up and play, even though you can't see? That would be called 'playing blind,' meaning your monitor's gone kaput.
 
Also, 'blank screen' could also be narrowed down even further - you say you tested the cabinet with a known working board.

Does the known working board coin up and play, even though you can't see? That would be called 'playing blind,' meaning your monitor's gone kaput.

it's not playing blind. but i think i figured out the problem. After inspecting the pcb , i noticed the old board has wires soldered on to it..i looked at the edge connector and i seen some wires were clipped so it looks like someone thought it was slick to just bypass the connector and solder the wire to the board.

So at this point im confident its not the monitor but the one connection and the edge connector..it might be easier if i can find a ms.pac man wire harness.
 
...it might be easier if i can find a ms.pac man wire harness.
Naaa, grab a manual and check your the wiring on your harness vs what the manual says....
Or worst case, pm me and I'll send you some detailed pics of what the color scheme on your harness SHOULD look like....
 
Naaa, grab a manual and check your the wiring on your harness vs what the manual says....
Or worst case, pm me and I'll send you some detailed pics of what the color scheme on your harness SHOULD look like....

This is a picture of the edge connector, noticeably there are broken wires, which is why they soldered them to the old board to bypass it.

img2012080300061.jpg
 
I see those stubs, where are those SAME color wires on the harness? The ones that USED to be soldered to your old board? Here is what I'd do, make sure the pins are in that connector, then take the same color wires from the harness and solder them right to those stubs! Bingo, working game! Too bad you're not local, I'd have that thing working in 15 minutes!
 
I see those stubs, where are those SAME color wires on the harness? The ones that USED to be soldered to your old board? Here is what I'd do, make sure the pins are in that connector, then take the same color wires from the harness and solder them right to those stubs! Bingo, working game! Too bad you're not local, I'd have that thing working in 15 minutes!

I'll give it a go, not much room to work with but its worth a shot. Not much on those stubs i'll have to strip just a lil.
 
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