Pacman with hum bar problem...

learpilot2

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I just got a pacman that has a hum bar (flag effect) in the maze on the screen. I noticed that I have a 6"x4" circuit board with a lot of resistors plugged in between the main pacman cpu pcb and the main edge connector. It looks factory. Is this the useless filter that everyone refers too? Do I just pull it out, and attach the harness to the main pcb? Is that safe for the machine? Will that alone fix the picture wave?

I also bought a new fuse holder and a molex edge connector to replace the old original one. This is the first I have made a new connector. I ordered from Bob Roberts, and it did not come with instructions. Do you just clip the old wires off one by one and transplant them into the new molex connector? Do you feed the wire through, attach a prong, crimp it, and then pull backwards into the connector, or do you solder each one to the wires. I bought a crimper, so I assume you don't solder.

Thanks for the help.
 
Yes, that is the filter board. Trash that demon. Just plug the connector into the board, its made to be like that. As for the hum bar, I cant say.
 
I just got a pacman that has a hum bar (flag effect) in the maze on the screen. Will that alone fix the picture wave? I also bought a new fuse holder and a molex edge connector to replace the old original one.

As for the hum bar, I cant say.

Hum bar is caused by the old fuse block and fuses on the floor of the cab. Sounds like you are replacing them, so that should cure it.
 
Yes, that is the filter board. Yes, just hook the edge connector up directly to the Pac board.

Yes, cut one wire at a time. Strip approx 1/8" of the wire and crimp the pin on. Insert pin in the new connector. NOTE: make sure that you put the pin in the connector in the correct direction. if you are uncertain what the correct direction is, use the old one for reference.
 
Hum bar is caused by the old fuse block and fuses on the floor of the cab. Sounds like you are replacing them, so that should cure it.

Hum bar is NOT ONLY caused by the fuse block. A burnt or dirty ground pad on the edge connector will also cause hum bar....
 
Hum bar is NOT ONLY caused by the fuse block. A burnt or dirty ground pad on the edge connector will also cause hum bar....

Indeed. Be sure to clean the "fingers" on the board with an eraser too.

Those are the most common sources.

It can be the B+ filter cap on the monitor as well. Happened to me.
 
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