Space Duel - Dead Board

Zinfer

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So where does one start at on a dead board? LED light is lit. Neckglow. Spot killer on. Marquee lit. I hear the crackle of the screen as it powers up. Ran a heat check on the pcb, fairly cool. Checked tap voltages +5 -5, +10 all check out good. Didn't see anymore taps to check. The two start button LED's are lit constantly.
I've never actually done a completely dead board before.
 
Yes. There's not much 'float' with it. I tried to meter it from the other side and it seemed to work ok. Almost needed a 3rd hand for that though. Are you thinking the reset may be stuck?
 
Oh yeah and the AVG chip. But out of the 15 or so SD boards I've repaired I've never had a bad AVG. Could be just lucky?
 
Oh yeah and the AVG chip. But out of the 15 or so SD boards I've repaired I've never had a bad AVG. Could be just lucky?

And I was told the AVG is often the culprit. :)
I bought a working board after my board tested bad in a working machine. Still need to resolve the bad board issue.
 
Sheesh, repaired 15 SD boards? Maybe we should take this to a PM. I've never repaired an initially dead board. If I get in over my head, it'd help to know who I could send it to for repair, if your accepting repair orders. But I would like to try stepping through the minefield othewise I'm not learning anything.
I'd normally just run it up to Alex as he's pretty close-by but he's been unavailable even to emails for the last couple months.

Oh yeah and the AVG chip. But out of the 15 or so SD boards I've repaired I've never had a bad AVG. Could be just lucky?
 
I did that previously with the +5 halving issue. I just picked me up a GQ-4x USB Universal Eprom programmer from MCuMall a month ago. So I was thinking of pulling the Eproms starting at J1 on up. J1 is fluctuating quite a bit from 1v to 2v, it's jumping around alot, where the rest of the Eproms on up are steady at around 4.26v. Never used an Eprom programmer before so this will be a learning experience. I'm not sure which Eprom to select from the drop down list.

First thing to do is reseat all the socketed chips.
 
Well that makes me feel better then. Hope Steven can get that back to me soon. I got one with a broke pin.

I've got 2 of the arcadeshop avg boards in 2 different space duel pcb's.Haven't had any problems with either one.
 
ehm.. 2532's - This is an Eprom right? You are able to erase and rewrite, right? I don't really know what I'm doing yet with this programmer. But I have run a Read and Verify on J1 and it checks out. Getting a 5E2AB Checksum so it looks good. May just move on to the next one.
 
Ok, ran all Eprom checks. The checksums are all good. Double checked +15 and -15 voltages on the board. The only thing that is getting hot is VR1 and VR2 voltage regulators for the - and + 15v. So hrm.
 
Well if the checksums equal what's called for then, the program should technically run enough to do a ram test. Could still be other problems with A and D lines. If it won't do anything in self test, it may be a bad 6502 CPU. Do you have another 6502 game to swap processors. I would put the unknown into a working game.
 
Just wanted to state that I'm running an AS AVG in my Space Duel and it works fine.

DogP
 
I'm half tempted to hook up the oscope to the x and y to see if I'm getting anything. I've tried flipping the service switch but nothing. I think Asteroids used a 6502 processor. I could try a blind game of it after pulling the SD 6502 and placing it in asteroids.
A and D lines?

Well if the checksums equal what's called for then, the program should technically run enough to do a ram test. Could still be other problems with A and D lines. If it won't do anything in self test, it may be a bad 6502 CPU. Do you have another 6502 game to swap processors. I would put the unknown into a working game.
 
I had a space dual board acting similar to yours. Voltages were reading right. I luckily had access to another working space dual cabinet. I plugged the pcb in and it worked. My problem ended up being big blue on the power supply brick.
 
Thanks for the tip, but I've covered that ground already. It has to be either the AVG or the 6502 CPU. Trying a CPU swap tomorrow. I'll bank on the AVG, but then - I already have.
 
Ok, swapped out the 6502, traded Asteroids 6502 for Space Duel, asteroids is playing fine. So that rules out the CPU.
 
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