Star Wars Arcade help

I don't think I have a chip problem. The game blind plays.

Cj

LOL - OK.

Digital logic / program might partially work BUT vector analog section doesn't. Lots of "chips" in all those circuits.
An oscilloscope is best for troubleshooting this, IMHO.
 
BTW, if logic board has gone bad (no or bad Xout/Yout), and you continue to power the monitor with spot killer "on", you do risk damaging the monitor. Then you'll have to repair both the logic board and the deflection/HV boards. So, please be careful; don't shotgun. Lots of threads on vector repair.
 
I had this exact same problem a year ago. It wasn't the rom/ram then. Don't know why it would be now. What's the odds that a different failure produced exactly the same results? Not likely. When I had it refurbished the guy just upgraded and replaced components. Basically massive tune up. And nothing I've read indicates that the spot killer is normally caused by a ram/rom error. I definitely don't really know what I'm doing here but I am an engineer and familiar with problem solving. Just doesnt seem like ram/rom is the likely culprit. I'm not getting any errors on the self test that aren't expected.

I've turned rhe brightness all the way down and only run it for a few minutes while I'm doing diagnostics, so hopefully I don't damage anything else.

What else can I check? My gut says something in the deflection board got fried.
 
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I had this exact same problem a year ago. It wasn't the rom/ram then. Don't know why it would be now. What's the odds that a different failure produced exactly the same results? Not likely. When I had it refurbished the guy just upgraded and replaced components. Basically massive tune up. And nothing I've read indicates that the spot killer is normally caused by a ram/rom error. I definitely don't really know what I'm doing here but I am an engineer and familiar with problem solving. Just doesnt seem like ram/rom is the likely culprit. I'm not getting any errors on the self test that aren't expected.

I've turned rhe brightness all the way down and only run it for a few minutes while I'm doing diagnostics, so hopefully I don't damage anything else.

What else can I check? My gut says something in the deflection board got fried.



RAM/ROM errors are just one of many things that can cause the spot killer to trigger.

The spot killer comes on when there is no deflection occuring in the monitor's yoke, which can be caused by either 1) a monitor issue, or 2) any game board issue that causes one or both of the XY signals to not be transmitted (which is actually a majority of possible game board issues).

If you are running an original black AVG chip, replace it. They all fail eventually, and will take out your monitor when they do. Replacements are available for $25 from Arcadeshop. That's something you should do regardless of any other issues.

If the game is playing blind, you will need to see if you are getting XY signaling after the DACs. Then trace those signals through the analog section. You could have something as simple as a blown amplifier in the analog section, or it could be a bad DAC, or it could be something late in the digital chain. But if the game is playing blind, much of the board is working, so that rules out some things. However you need more data to be able to debug further, and that requires either a logic probe, and/or a scope.

You can also take a DMM, and measure the DC and AC values on the XOUT and YOUT test points on the main game board, near where the pots are. Post all four values here (X DC, Y DC, X AC, and Y AC).
 
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Ok. So I can probably check the AVG chip if you could help me know where that is exactly and how I know if I have an original.

The middle section sounds beyond my capability.

I can probably test the DC and AC if you could help me know exactly where to probe. What board is that on? Where to I hook up the multimeter.

Thank you for the help. If I can figure out at least what board the issue is on I can probably find someone to ship it to for repair


Cj
 
One other symptom i should mention. I was getting this problem intermittently recently. Usually would start if I left the machine on for more than 20 minutes or so. But I would turn it off and it would alwayw work the next time I turned it on. This time it stuck. So not sure if that helps a diagnosis any.

Does the AVG chip get replaced when you install a multigame kit? Is that part of rhe replacement?

Cj
 
I think I found the AVG chip. Looks like an original to me.

Cj
 

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Yep, that's it. I had the same problem. Replaced it with one from Biltronix. If it's not the problem I would replace it anyway as they do go bad a bunch.
 
Ordered one from Arcade shop. I kinda doubt this is the main issue, but can't hurt to put one in. Could this AVG chip cause the issues I've been seeing? Screen going wonky when machine is on for 30 minutes (I guess because things heated up) and then final goes wonky all the time w/ the spot killer on?

Cj
 
Was emailing another guy who does repairs. He informed me that if it blind plays (which it does), then it's definitely not the AVG chip. Confirms my suspicion that this problem is elsewhere.

Andrew, can you give me a little more help on how to check those X/Y outputs after the DACs?

Cj
 
OK thanks. I was looking at some online photos and couldn't find the labels. But I'm sure I can find them tonight when I pull it apart if they're labeled right. I'm looking at the layout in the manual and the TPs aren't labeled on it. :( There are a lot of test points on that board!

Cj
 
Was emailing another guy who does repairs. He informed me that if it blind plays (which it does), then it's definitely not the AVG chip. Confirms my suspicion that this problem is elsewhere.


Fascinating, I'll have to tell that to the many vector boards I've repaired in the past. Damn, it's true, you learn something new everyday. :cool:
 
Well, I'm just relaying what I was told by another guy that repairs them. :) I can't vouch for the validity.

Cj
 
A bad AVG will usually screw up the vector generator, which will send the CPU into watchdogging mode (i.e., continuous resets), which will make the board unplayable, and not play blind.

That's not to say it can't play blind, but it's typically not the case. A bad AVG will also frequently cause bad/random/overvoltage XY signals to be generated and sent to the monitor, which will blow the deflection board. This is why you don't want to risk running an original AVG chip, as most of them have already failed, and any existing ones are ticking timebombs.

As mentioned, the AVG is likely not your issue, but it's something you want to address regardless. And it's good to know you have a good one if you are going to do other debugging.

FYI, douglasgb and I repair Star Wars (and other vector) boards, if you are looking to send it out to someone.

(Also, you should update your profile to include your location, and enable it so it is displayed with your posts in the upper right corner, as most folks here do. It can help when trying to find local people for various purposes, including repairs.)
 
Yes, I will likely need to send this out to someone, but I wanted to do at least a minimal bit of diagnostics to see if it was something easy to fix first. I ordered the AVG, so I'm gonna put that on and see if it does anything. I might just pull the deflector board and bring it into work to have my EE friend look at it to see if there are any obvious blown parts or bad solder points.

Thank you all for your help.

Cj
 
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