NBA Jam graphics problem

JukeboxJon

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EDIT nvm im an idiot and forgot about the k7000 having the 50-60hz pot and apparently both k7000s i had were set to where capcom boards like them but not nba jam 😂😂

Any idea what could cause this fold over at the bottom and stretching at the top of this NBA Jam PCB?
This is a board problem NOT A MONITOR problem. Every other game board looks totally fine every k7000 I put in it has the same issue. If I test the k7000 with a different pcb it looks completely fine no problems. All roms pass. Voltage measured from the roms is spot on. I have reseated all socketed chips but have not done a full socketed chip cleaning with the deoxit treatment yet. Cleaned edge connector.

Ive checked a street fighter 2 boar and marvel vs capcom with the same exact monitor and set up and i have no issues with the vertical
 

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Last edited:
Yeah, that definitely points to something on the NBA Jam board itself, likely in the sync or video output section. Since your other boards (SF2, MvC) look perfect on the same setup, the monitor's ruled out. Check the vertical sync circuit, specifically the LS74 / LS123 / LS86 area that handles sync shaping.
Also inspect the video output section near the JAMMA edge for any cracked joints, lifted traces, or out-of-spec caps. NBA Jam is known to have flaky sync timing when certain components drift. If you've got a scope, check the sync pulse width, it's probably distorted or missing a few microseconds, which can cause exactly that top stretch/bottom fold.
 
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