CPS-2 Tile Flicker Issue *updated*

[Pr3tty F1y]

Picked up a 'broken' CPS-2 board. I already removed the battery, installed Phoenix Edition roms, cleaned up some corrosion on a few SMD chips (seems very random where it appeared), fixed a bent pin in one of the board sandwich interfaces (I'm guessing this was the main culprit that was causing it to not work), and dumped all of the ROM chips and everything matched MAME.

Internal memory check reports no issues. All RAM/ROM types report as OK (which is probably somewhat of a lie )

I've reseated the B-board several times.

While I have some random tile flicker that I plan to eventually address (maybe it's just because I'm missing red color... I have my doubts...), my main problem is that there is no red channel. Absolutely nothing. It just shows as black.

I was wondering if anyone knew off the top of their head at which sets of LS logic chips I should be targeting for the red color gun. Any tips would be appreciated!

 

[Pr3tty F1y]

And to close the loop, I NOW HAVE RED!!!!

It was a corroded broken trace between the via directly connected to the JAMMA edge connector pin 12 (red color channel) back to it's respective resistor pack at RA4. So easy that even I/a caveman could do it.

Still have some weird rectangular box tile flicker that appears consistently (i.e., it's not random tiles), but not during most of the game play portions of X-Men vs. Street Fighter that this board currently is.

As all the ROMs tested good... maybe corrosion in the rom sockets or elsewhere. Memory test still shows everything as good... will have to continue to troubleshoot.

 

[Pr3tty F1y]

I figured it was better to re-title the thread than make a second post.

With the red channel issue fixed, anyone have thoughts on what would be causing this tile flicker as seen on Rogue in the X-Men vs. Street Fighter intro? It definitely seems like a background tile issue as opposed to sprites.

I'm thinking it may be a bad inter-board connection, but I've re-seated the board numerous times and all of the pins are straight now. I guess I can test each of the few hundred pins for continuity