Galaxian PCB Help

JoshBrown80

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Donor 2011
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Hey guys,

Just got a used Galaxian PCB off E-Bay, and when I tested it with a JAMMA adaptor, I can play the first level fine usually..(sometimes i cant even make it through the first level without a reset)then either the board resets, or I just dont get the second level....I can still fly and shoot, which is kinda cool, and the background keeps moving...I measured voltage at the edge connector and am getting around 5.1 volts, however, on one of the 74 series chips twoards the bottom edge of the board Im getting a little over 4 volts.....so I did some poking around and I am getting 4 volts on the large 10000uf caps on the board...they have not been changed....does it sound reasonable to suspect that those caps could be bad and causing the issue? Anyone ever seen this type of failure before? Any help you guys can give would be appreciated...
 
Sounds like you won the board from board member MrClean. That sounds just like the symptoms he was describing.

Bad voltage can cause all kinds of issues. If those caps are original, I'd replace them.

But also take note of the rest of the circuit and/or what's coming into the board. The fuse holders are notorious for causing problems. I had a Galaxian board that literally had the recifying diodes crumble into pieces when I removed them from the board.

So meter your voltages from the harness backward and see what you get. Note that from the harness backward you should be measuring in AC not DC.
 
Just a bump on this thread for future searches...

changed the caps out and that did the trick :)
 
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