New (for me) Asteroids, screen went weird

bteeter

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Aloha All,

(This is a repost after realizing I posted in the wrong forum, sorry about that!)

I just picked up an Asteroids cab from a guy upcountry. It worked fine yesterday and today, but tonight the screen went all hamma jamma. Take a look at these pics:

http://imgur.com/a/0Nlia

(Edit: That is the self test screen.)

The cab came with a second board in a static bag, but the edge connector was hacked up and 2 wires soldered to the board, so I can't just swap them out. Anyone have any ideas on where to start to fix this guy?

I'd like to try to swap out the boards, but the edge connector has 2 wires cut from it and soldered on the board its using now.

Thanks in advance!
 
Looks like a board issue.. Just curious what the +5v test point on the main PCB is reading?? Test point is on the top front of the main board.. Also clean and reseat the edge connector. This is where I would start.. I will have to look up the wire diagram on the harness where goes into that connector. What they prob did was soldered the power right to the board??

You live in Hawaii?? Im Jealous...
 
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Looks like a board issue.. Just curious what the +5v test point on the main PCB is reading?? Test point is on the top front of the main board.. Also clean and reseat the edge connector. This is where I would start.. I will have to look up the wire diagram on the harness where goes into that connector. What they prob did was soldered the power right to the board??

You live in Hawaii?? Im Jealous...

Thanks for the tips, I will check it out tonight. Yes, it looks like they cut the wires from the connector and soldered them on the board. I'm guessing the connector was shot or oxidized. I'll have to look at replacing it.

Yes, I'm in Hawaii on the island of Maui. I was really stoked to find an Asteroids game on the island, I did not think there were any left. It worked for a bit then started flaking out. No big deal I can fix it, I just need to know how. :)
 
Is this how the game sits now??

MrhHsh.jpg


My guess is the 5v finger is burned up and someone bypassed it. A lot of Ataris do this. Come to think of it, 3 of the 4 in my game room were like this when I got them. I always reverse and correct:
http://www.therealbobroberts.net/pace.html
I also re-pin all power, ground, and sense lines in the edge connector.
You say the spare board has wires soldered to it? I am guessing if you track them down you will see they are +5 and ground. My bet is that board is bad as well. Why would you pull a board modded specifically for a cab??

As to your display problem. Will it coin and play save the image is all wonky?? I actually just fixed one doing something similar to what yours is doing. Keep in mind I sort of ham fist my way though a lot of repair work, learing as I go, but I am thinking its in the output section. That is the "silver" section at the same end of the board as the finger board. The DACs, a handful of OP-AMPs and 3 voltage regulators are the main parts in this section. In short its job is to convert the digital aspect of the game to the analog signals expected by the monitor. In my (limited) experience you would have a different effect if it was before the output section. Large or small objects, segments out of place or missing, unexpected angles in vectors. Things you would expect if your "math" was effected on the digital side. Your swooping and curving lines are typical of what I have seen with conversion to analog in the output stage.

Grab a meter, set it to DC, and test the X and Y outputs. Granted, its an odd test. The result could also be determined by the speed of your meter. My notes on Asteroids have, in test mode, X at about -.3v and Y at about +.155. Again, this may be determined by my meter. Switch back in game mode. The values should shift. If one is stuck that axis is a good place to start.
 
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