stargate problem help

chips4sle

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ok so i did the 4164 ram upgrade
new socket for the cpu
rebuilt power supply

im getting these green dots or static on the screen
and it will reboot randomly

also getting ram errors randomly

last but not least the the sound works when you hit the test button but not when you play a game

pics to follow
 
here are the pics
 

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first thing i'd check is the +5 volts dc coming out of the power supply and again ON the board maybe on a chip leg
trying to detect a bad connector
weak pin inside the connector
cold solder joint on a header pin
some sort of problem on the power supply

hopefully the +5 volts is low and needs adjustment UP

power supply capacitors dried up putting out screwy readings
power supply needs rebuild

might be a connector is burnt
look for "brown" or "cooked" white plastic connectors

whats the 12 v putting out while you're there

good luck
 
that could be 1000 different things. YellowDog indicated in his seminars that a lot of the TTL on these boards were pushed to their limit, so they're reaching a point now where they crap out a lot. :(

haven't seen it on Stargate, but did have a friends Joust create like tearing on the moving objects and it eventually turned out the MPU was getting 4.2v to the chips. :)

I've found a few new wrinkles in low +5 on the linear power supplies last weekend, so that's exciting.
 
I always replace the headers on the power connectors on all boards and the crimps in the harness. The original pinch style Molex connectors and round headers were fine for the couple of years the games were intended to last. Replacing the filter capacitors on the CPU/ROM boards is also a good idea.

Since you are getting random memory errors, it could be a bad decoder socket or dirty pins on the decoder prom.

Kirk S.
 
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