Moon Patrol Graphics Issue (Level #2)

Anthony605

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I am having an issue with my Moon Patrol board set. The game plays great and the sounds work well. There are no graphics issues on level #1. When I make it to the second level, there are vertical lines through the background sprites. I attached some pics showing the issue. As you can see, level #1 is fine. Any idea where I should look on the board set? Thanks!
 

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I believe the scroll circuitry is in the bottom board, I would make sure the interconnects are firmly seated, there may be a connection issue.

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I am having an issue with my Moon Patrol board set. The game plays great and the sounds work well. There are no graphics issues on level #1. When I make it to the second level, there are vertical lines through the background sprites. I attached some pics showing the issue. As you can see, level #1 is fine. Any idea where I should look on the board set? Thanks!

Probably a bad ROM / socket / connection on ROM 3H on the "M52-E-C" scrolling playfield board.

The city just junk bank switched with the nearby mountains, so if the near mountains look fine on the beginner course, all of the shared surrounding circuity should be fine.
 
I agree with Mark with a ROM issue (most likely connection). You can also flip the last dip switch up on bank 2 and run the onboard diagnostic. Typically, I would swap the bottom board with a known good one (just to isolate issue there). I see a lot of corroded legs on the BiPolar PROM's too (so be careful if you're thinking of pulling to straighten legs and clean). I would also remove the 10uf blue 'Teardrop' tantalum capacitor on the sound board. I've seen a ton of them fail and they do so shorted, which pulls the power down for the entire board.

~Brad
 
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