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dr_myslihiiri

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I bought a Japanese Mars Matrix CPS2 B board a while back, and when I first got it, it worked without an issue. When I fished it out of storage yesterday and plugged in again, it began exhibiting visual glitches, including vertical lines running down the screen and corrupted text.

Reseating the B board did not immediately fix the problem, but nudging it a little did. I guess this is down to a connector not making proper contact with the A board. At first blush, I couldn't tell if any of the pins were bent.

Does anyone happen to know which particular connector is responsible for passing down the graphics signals, so I can have a second look? Is there anything else I should check?
 
Sometimes a firm press is required, as in seat the B board on the A board then give a firm but sensible press on the B board.

Other than that, sometimes a reflow of the solder on the pins can help.
 
Also I would recommend using the original clamps that keep the boards firmly together
 
Oh, I forgot to mention that I already tried using the original clamps, and they made no difference. Other B boards also work fine, so I'm inclined to believe the problem is with the MM board. I'll make a point of checking the connector solder joints on the PCB.
 
Then indeed the solder joints on the A board connectors would be the next suspect
 
Try taking the B-board out of the case and put it on the A-board directly.

If you look inside of the B-board there are four holes where plastic pegs are that the torx screws go in. If one of these pegs break there is essentially nothing providing tension upon one of the four A to B connectors.

My X-men COTA had this problem in the bottom right corner since the peg was broken off and missing. The other peg was barely hanging on. Gotta love ABS plastic.

Here are some pictures to illustrate. Without that peg there, the board can flex upon insertion to the A-board. The screws torque is what prevents it from going up. With my board it sometimes wouldn't boot, other times vertical lines would appear.

One of my pegs was barely hanging on, so I glued it back.

e5hl5Qc.jpg


The underside where the screws goes through the peg and into the B-board.
ZulBuJf.jpg


How I fixed it, nut and bolt.

9OZmPzk.jpg
 
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Thanks for the tip! I'll check out the state of the pegs on my case when I have the time, and report back.
 
I have never seen solder problems on the 96 pin connectors (A or B board). If no bent/broken pins, check for broken case pegs, as ChuChu suggested. If no success with those, check and re-seat all socketed chips on B board.
-ud
 
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