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I appreciate anyone willing to take the time to put in their two cents.

I have a y unit rev 2.0 MK pcb. The board boots fine with no cmos errors. After about 30 seconds it goes into the test menu by itself and then selects diagnostics and switch test on its own. The board stays on this screen with test button locked on. I am able to test player 1 and 2 controls for the most part but high kick, low kick, and low punch do not register. Occasionally the service and high kick buttons will register on their own.

After about 30 more seconds in this test menu the board will lock up. I can switch off the power and the cycle repeats itself. Seems that times decrease with subsequent boots.

It seems to me that the pls135 at U40 is getting warm to the touch. I suspect this might be bad as the schematics say this is an address decoder pal.

My main question right now I guess is if this being bad could cause the behavior i described. I would like to know if im barking up the wrong tree.

I am starting to use an oscilloscope to troubleshoot this pcb for the first time so I am inexperienced when it comes to the scope. I do see some lines that are tied high on this pal with the occasional activity when scenes change on the screen. My inexperience prevents me from understanding if this is normal,

I appreciate any input as at this point I feel I'm chasing my tail. I would like to avoid shotgunning chips to fix this board so im begging for any help anyone is willing to give.
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