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If you have an ESR meter that shows ohms on the screen, you can use it as a high frequency milliohmmeter to check pins to ground to see which one is ever so slightly lower and the source of the grounding problem.

Bus transceivers have enable and direction pins. Check those to see if there's any correlation to the pulses.

Post a pic of the PCB.

Use a logic probe and look for missing signals on those red flagged RAMs.

For graphic corruption, Op will need to reflow the 2 Jaguar chipset chips - Tom and Jerry. If parts of RAM are missing from the memory map you'll get corruption, but it's on specific graphic elements, not across the whole screen. There are built-in self tests if they believe there are RAM...

Is that the PC based boardset or the Jaguar?

02xx or the color PROM. Never touch the 05xx. Legs are too fragile to f*** with.

If you're in Italy, contact @caius

I just tack it across the joint on the bottom of the PCB. Anything from 1K to 10K should work. Mecha: It's not that it comes back, it's that the table gets in a corrupted state.

I recommend you ask over on the Arcade Otaku forum. Lots of Europeans over there. I've fixed a few of those MK4 boards, but with the current tariff situation, I'm not doing international repairs.

Is the speaker wired to 10 and L on the edge connector or is one side of the speaker connected to ground? You cannot ground one side of the speaker on that game.

There's a cap labeled CC1 by where the battery goes on the CPS2 cart PCB. It's know to short across it with a screwdriver to drain any charge holding the encryption table. You could also solder a 1K resistor across the pins of it. That will bleed down any voltage when you power it off and cause...

You should create a GitHub acct and put your files up there. :)

Nice fix, Yorge!

That's the self test going... If it's restarting look closely at the screen for an error message to flash by momentarily. I'm OOS on the rebuild kits only because I'm low on one of the parts for it and need the stock to do repairs. Now that VCF Southwest is done and in the books as of a week...

You needed a 74L86 and not an LS or blank... the pinouts are different.

You can reuse GAL chips off other boards. Beware that GAL chips can have bad outputs and still program correctly.

Don't remember. That was long ago. This board will also have problems with game switcher boards as well since those extra pins won't be switched by any relays. Just now seeing your post. Went to ABQ and back over the weekend to pick up a truck/trailer load of fairly rare vintage Unix systems...

Replace the 3 bad 74HC541 chips...

...----------- Next, the bane of RevX boards everywere are leaking SMT caps. If you have a board, recap it. Hopefully you get it before the caps p*ss all over the board and corrode traces. I have one here that I cleaned, recapped, and patched several traces on but was still unstable. The cause...