Newbie fixing a Q-Bert... audio and video troubles

eBayfreak

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Hello everyone, I've been lurking here for a while but this is my first post I think... I've restored a machine before (Jump Bug by Rock-Ola, mostly cosmetic restoration) but this is the first time I've done any real troubleshooting.

I've got a Qbert with two main issues. First, the video is messed up; the image starts at the middle and the bottom half of the image shows up at the top; other parts of the image look a bit garbled as well (these pictures are lousy but you get the idea):

qbert1.jpg


qbert2.jpg


The monitor is also flickering but that's probably a better question for the monitor forum.

Also, there is no sound; it says "I am turned on" when powered up but is silent thereafter. When the test button on the sound board is pressed, there's a single tone that plays for a few seconds and nothing else.

So far, I've reseated all the chips on all the boards and checked all connections... what's the next step? Thanks for any help!
 
First, check the power supply (upper right board) and see if all your LEDs are lit. You may be missing a specific voltage, especially on the +30v line.

Next, pull that filter board off (upper left) and check all the solder and traces on the backside. It's not uncommon for some of those traces to be bad, nor to have a lot of cold solder joints.

Might not fix it, but it's a place to start...
 
Thanks for the posts everyone. Nothing's changed as of yet.

Modessitt, I just now removed and checked the filter board with a continuity tester and everything seems ok. All LEDs are lit on the power supply, so I'm assuming it's ok.

Mike, thanks for the link.. the flow chart is very helpful. Is there a good place to get the chips that it recommends to replace?
 
Yes, I got it about 100 miles south of St Louis from a Craigslist post. I got a Popeye and Joust too (Popeye has minor monitor issues but looks/plays great; Joust seems to have a bad power supply and I don't know what else yet). These three ought to keep me busy fixing for quite a few weekends.
 
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