Tempest issue help :)

prOk

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Here's a vid of my tempest:



It seems to just pick wierd times to do this freakout. Most of the time it does it on the attract mode with the TEMPEST logo, but sometimes it does it during gameplay.

I thought it to be heat related, but he game can be on for an hour, freak out and come right back again. Some times it freaks out and goes black but flipping the test mode switch brings it right back without powering the game off, so i'm doubting heat.

In test mode, shows no errors at all, picture is solid and stable with the exception of these freakouts. The AR2 is totally rebuilt and spot on for voltages, monitor is capped with lv2000 and the big blue is new. The spot killer does come on during the wierdness.

Anyone got any ideas?
 
When the screen goes out, can you still start a game and hear it play? Trying to identify whether it is a PCB or monitor issue.
 
I have reflowed the headers and repinned the harness. Pulled cleaned and reseated all the socketed chips. Thinking bad socket maybe
 
Yea, bad socket or even a bad 2901 bit-slicer. Those things get hot so you can either shot-gun all 4 of them or feel for one that seems hotter than the rest. It doesn't seem like the problem last long enough to try freeze spray on it.
 
If you can dump another monitor chassis in there....do it to try to confirm it is PCB related. My guess would be main PCB - If connections are all verified good and solid....check the 2 ROM's in row 3.....clean them up good....make sure the sockets are good....check for activity with a probe. With the spot killer kicking on after playing....that is my guess...bad/dirty ROM's....screwing up your vector generator circuits.....and you getting that crazy output on the screen. Also flip in a new CPU....
 
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A dumb idea I just thought of, I *doubt* it...BUT....

You keep a cell phone on you? Iphone/Att/Tmobile phone that uses GSM (which happens to be very electrically noisy?). If you keep it in your left pocket, and you're standing directly in front of a tempest...your putting your cell phone very close to the boardset, specifically the roms and CPU right there. That would also explain the randomness of it.
 
I have a boardset that does that too. Not AUX board related. Still working out what the problem is.
 
I just had a Tempest doing similar stuff in a friends bar. I had already replaced the edge connector...it looked suspect....so, I pulled the motherboard. It tested fine in the shop. Back at the bar, I started probing the A/R II board, everything looked good. I swapped big blue and examined the power brick....problem remained. I was becoming stumped.....had the back off and the game running.....something made me run my finger across the fuse block....BINGO! The 20 amp fuse was so hot it almost blistered my finger. New fuse and fuse holder....problem gone. I always suspect these fuse holders on Atari games, the 20 amp fuse location is always burning up. This paticular one (visually) looked perfect....so I assumed it wasn't a problem. I was wrong.

Edward
 
I just had a Tempest doing similar stuff in a friends bar. I had already replaced the edge connector...it looked suspect....so, I pulled the motherboard. It tested fine in the shop. Back at the bar, I started probing the A/R II board, everything looked good. I swapped big blue and examined the power brick....problem remained. I was becoming stumped.....had the back off and the game running.....something made me run my finger across the fuse block....BINGO! The 20 amp fuse was so hot it almost blistered my finger. New fuse and fuse holder....problem gone. I always suspect these fuse holders on Atari games, the 20 amp fuse location is always burning up. This paticular one (visually) looked perfect....so I assumed it wasn't a problem. I was wrong.

Edward

So it gets mega-hot but still doesn't blow the fuse? No glow or anything? That's crazy.
 
So it gets mega-hot but still doesn't blow the fuse? No glow or anything? That's crazy.

Yes....and yes.....and I agree, crazy! It was a "normal blow" fuse too.

Edward

I have actually seen quite a few Sanyo 20EZV's do pretty close to the same thing, but there is usually very light orange glow on the fuse.
 
Here's a vid of my tempest:

It seems to just pick wierd times to do this freakout. Most of the time it does it on the attract mode with the TEMPEST logo, but sometimes it does it during gameplay.

I thought it to be heat related, but he game can be on for an hour, freak out and come right back again. Some times it freaks out and goes black but flipping the test mode switch brings it right back without powering the game off, so i'm doubting heat.

In test mode, shows no errors at all, picture is solid and stable with the exception of these freakouts. The AR2 is totally rebuilt and spot on for voltages, monitor is capped with lv2000 and the big blue is new. The spot killer does come on during the wierdness.

Anyone got any ideas?

Just repaired a Tempest main board with a somewhat similair problem.

Screwy graphics all the time, the first test mode screen would come up for a split second and then disappear, and no errors in the second self-test screen.

Screen would blank out for several seconds and then come back up. It did this about every 30 seconds.

Bad 2114 ram @ K3 fixed it.
 
It is possible to have bad vector ram an it not show in self test as well. youd have to run a long ram test with a fluke to determine.
 
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