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Terminator 2 U99 Issue

Lastsix

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I have a Terminator 2 board that boots but shows a U99 error. The U99 was pulled out and put into a Mortal Kombat; where it ran ok. The game will try to boot after self-test into a black screen with no sound but after 40ish seconds arnold schwarzenegger's face pops up (the hi-score screen). I can see no visible damage; any ideas on what to check first?
 
the 40 pin AUTOERASE chip by the U99 Williams Custom Chip(tm) can cause all kinds of weird stuff on Y-unit games. the original socket is single wipe, I don't know if it's corrosion on the legs inside the socket or what but you get a lot of mileage out of replacing the socket. especially if you have blackout or reset issues. the T2 at my job is where I made this discovery lol

also for whatever reason T2 is one of those games that works better with the voltage a little bit low from all the games I've worked on. 4.95V to the chips seems to be the most reliable.

further reading: https://www.arcaderepair.net/mechas-essential-power-supply-guide-remastered/
 
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Is it a dumb idea to remove the socket and solder the chip to the board? I noticed mortal kombat 1 does not have a socket on its u99.
Is there any way a bad ram trace can cause this error?
 
Is it a dumb idea to remove the socket and solder the chip to the board? I noticed mortal kombat 1 does not have a socket on its u99.
Is there any way a bad ram trace can cause this error?
Custom Chip and AUTOERASE chip are different components. I've never seen T2 with the Custom Chip socketed. they're kind of a nuisance to work with. I stole a socket from a High Impact Football board a couple years ago and soldered the chip in direct, it's apparently missing a connection somewhere cause it has graphic glitches now that won't clear. it will require some effort to desolder it back out again.

it's a thing where reseating the Custom Chip is the necessary first step if you get a U99 error. you already tested it in another game and it was good there. I fixed a T2 for a guy a few years ago thinking the Custom Chip was the fault, and it wound up being a BAD AUTOERASE chip. so I had to rob that from somewhere else in my collection.
 
The autoerase is U115 right? I have another board I can steal one from; do they have any kind of security?
 
The autoerase is U115 right? I have another board I can steal one from; do they have any kind of security?
it's a bunch of little PAL chips that are supposed to be for security in the vicinity of the CMOS.

and yes AUTOERASE is U115. manual calls it a PLD Autoerase Ctrl. those are the same between NARC Z-unit and Y-unit games, as are the Custom Chips.
 
Swapped the u115 from another board and no change. The socket on the board looks ok but may consider replacing with a new socket.
 
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