Space Zap: Gameboard or Monitor Issue?

mjansma

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Space Zap experts… I need your help.

I recently picked up a Space Zap. The game was working great, but the monitor was a little tired so I decided to cap the chassis. I could tell it had never been touched since it left the factory. I washed and then dried the chassis for a few days before starting. All I swapped out were the caps on the board and the one under the chassis. I didn't mess with the B+ filter cap can yet because honestly it looked like a colossal PITA and the B+ was dialed in solid at 73 volts per the manual. The only other minor change that I made was swapping out the micas and thermal paste for silipads on the two bottle cap transistors.

When I put the monitor back together and plugged it in, there was no smoke or pop. The B+ was still solid at 73v. However, now I have another issue? It seems like it is resetting every two seconds. In test mode, there are a series of three faint beeps coming through the speaker, which is strange because the manual doesn't say anything about beeping in test mode.

I'm not sure if this is a board issue or maybe something I accidentally grounded on the chassis while installing the cap kit.

My plan for this weekend is to take everything apart again, double check the work, and reassemble it. I did move the cab across the garage floor after I pulled the chassis out. Maybe something got loose.

If anyone has experience with a malfunctioning Space Zap, please chime in with your thoughts. I have attached a few videos below of what the monitor looks like when I fire it up and the beeps I'm getting.

Screen in Game Mode (Video)

Screen in Test Mode (Video)

Beeping (Video)


I'm kicking myself with this one. I should have just left it alone.
 
I assume you've searched and found my Space Zap Tech info thread? (link in the signature if not)
I did use it for changing out all of the tantalum caps and adding the heatsink. it was extremely helpful. Thank you! The game ran really well afterwards.
 

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I did use it for changing out all of the tantalum caps and adding the heatsink. it was extremely helpful. Thank you! The game ran really well afterwards.


How did the backplane look? this looks like connection issues with the cards.


How are the power connectors on the blackplane? they get cracked solder joints a lot. If things were being moved around when working on the monitor it may not be making connection it was before.
 
How did the backplane look?
Really good. Nothing jumped out at me. The backplane, the header pins, and the cards all looked clean. No rust or corrosion. It had definitely been serviced somewhat recently and I was surprised how clean everything was compared to the rest of the inside of the cab.

I'm going to take it all apart again this weekend and double check for cracked solder joints. I will report back once I know more.
 
You image looks like cpu board issue and/or the 17 i/o custom. odd that it would suddenly die so its most likely a connection issue somewhere.
 
You image looks like cpu board issue and/or the 17 i/o custom. odd that it would suddenly die so its most likely a connection issue somewhere.
Update: This is definitely a board issue and not a monitor issue, and it's very fickle to say the least. I pulled the boards last night, cleaned all of the socketed chips with DeOxit, and reseated them. The game fired right up and worked last night and again this afternoon. I just played for about 10-15 minutes and then shut it off to have dinner. When I came back out tonight it's back to beeping/resetting.

I did notice during the last 5 minutes that I was playing before I shut it off that it was starting to get glitchy. Just little flickers here and there on the screen in random spots.
 

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I'm circling back to Space Zap since I finally had some time to do more work on it this weekend.

I rebuilt the power supply and decided to run both the Mark Spaeth and David Turner RAM tests. The David Turner test gave me no errors, but I noticed it said "Lemory" instead of memory, and "tert" instead of test.

I was expecting Mark's test to come back with a U21 error, but instead got "U25" which doesn't exist on the RAM cards. If you watch the video I linked, the picture starts up fine and then slowly degrades as it warms up. This also happens when I run the game.

RAM Test Video
 

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