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Ms Pacman Mini Missing Red
Question from Steve: I have recently bought a Ms. PacMan Mini and the cabinet was trashed from water damage. I got it home and fixed a couple of bad connections and got it running. The image on the monitor looks off so I adjusted it and got it looking good but shortly after that it would lose the red color if I bumped the machine and eventually lost red all together. I checked out the monitor and it seems like the monitor is good because I can adjust the red and red drive and get red on the monitor but still don’t get red on the graphics on the game. I can make the screen red but graphics that are red in the game i.e. the red ghost and the cherries show up black. It seems like I am missing red on the input to the monitor. I am looking for some guidance on what to troubleshoot to see why I am not getting red to the monitor. I am new to working on arcade machines and would appreciate any advice you could give me.
Thanks,
Steve from Owasso, OK
1 answer
Response from Jonathan: Steve,
Sounds like you might be having some problems with the red input wire coming from the board to the monitor. We recommend tracing this wire from the harness to your monitor chassis to see if it’s making a good connection. Here’s a pinout list for Pac Man type machines from Two Bits: http://www.twobits.com/pacpinouts.html. You can use the continuity check on your multimeter to see if the wire has any breaks in it. Check out our post on Checking Fuses With A Multimeter for more information about continuity. If the wire is making a good connection, you might try touching up the solder on the back of the red pin on the monitor chassis. These pins like to come loose sometimes especially after years of unplugging and plugging in the connector.
Something else to keep in mind is that you might still have a monitor problem even though the red on the screen increases when you turn the corresponding adjustment knobs. Check out our post on Checking A Monitor Tube for information about the color drive transistors. It could be that your red drive transistor could be out on your monitor.
Hope that helps. Thank you for your question and good luck with your repair.
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