Star Wars Upright Help

darkrpa

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1st off I would like to thank the group for the wealth of knowledge I have gained lurking, reading, and researching. Here is what I have going on at the moment..

What initially was happening, was the game turn on and fire up, then after a few minutes or longer, it would cut on and off. (3 Main board lights would come on and the monitor board light ) . This was somewhat intermittent to the point of " I need to see what is going on. " Tested Power brick and had issues with the 36v at Pin 6 and Pin 7. I was checking them correctly, not grounding at Pin 5, as that would give me half value. No blown fuses. I pulled the power supply and there was a burnt wire connected to the Bridge Rectifier. I checked the bridge rectifier between legs, both ways and all 4 diodes seemed fine in there. (checked with BB disconnected) I replace the wire connector and also put in a new Big Blue. Pulled 3 boards and edge boards and cleaned all the traces, nothing bad or burnt. After. that, all was good with the PS Voltages it seems and checked voltages at the ARII board. That is all fine and dandy. Cleaned main PCB board and it did have much dirty filth on one of the chips above the muffin fan. (* Note to self and others. * ~ Check your fan(s) occasionally. I have had this machine for 30 years with very minimal use and never thought it could get so gross with brown fuzz. Also replaced the power cord that was long overdue of being changed with the one I bought many years ago that was prewired with the Atari Molex. With all that said and done, i did have her back up and running for a good day. Was hoping all that good time was behind me. BUT...Yesterday, I had fired it back up and it was running, walked away for 15 minutes and came in to nothing going on.

I just Pulled PS out and checked to see if that same wire end that had fried before, and it looks fine. I did check the bridge rectifier again just now, but with the wires from BB still attached and BB to check that again. I think i need to take one side of wires off BB to accurately check that again correct?

I am still getting good Voltages to the main board as of now, but 3 lights Mainboard and Spotkiller light is on. Sidenote if helpful ( Board with the 3 red lights, there is 4 chips about centerish of that board that get hot, I know things get warm and hot, but those seem more warmer than the others ). Thanks for reading and your time.
 

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Last edited:
You might be shorting your audio amplifiers with those two metal screws. How long have they been there like that?
Those have been there since I have had it.

I can get it to power up and stay on for about 10 minutes, both yesterday and today, but only in the morning when it is cooler inside the room it is in. I just checked voltages again on ARII board while it was running and under load and they are fine. I'm leaning into the guess that I have cold solder joints somewhere on the main boards somewhere.....
 
What voltages are you getting on the ARII? I would first recommend the usual... With the game board connected, adjust the trim pot on the AR board until you get 5v. If you can't get the trim pot to adjust the voltage, you probably need to replace the LM305 voltage regulator. If you haven't already replaced the 2N3055 bottlecap transistor, you definitely need to. Also, I would replace all of those smaller blue caps on the board. The one on the right side in your picture looks possibly damaged. Hard to tell.
 
What voltages are you getting on the ARII? I would first recommend the usual... With the game board connected, adjust the trim pot on the AR board until you get 5v. If you can't get the trim pot to adjust the voltage, you probably need to replace the LM305 voltage regulator. If you haven't already replaced the 2N3055 bottlecap transistor, you definitely need to. Also, I would replace all of those smaller blue caps on the board. The one on the right side in your picture looks possibly damaged. Hard to tell.

What voltages are you getting on the ARII? I would first recommend the usual... With the game board connected, adjust the trim pot on the AR board until you get 5v. If you can't get the trim pot to adjust the voltage, you probably need to replace the LM305 voltage regulator. If you haven't already replaced the 2N3055 bottlecap transistor, you definitely need to. Also, I would replace all of those smaller blue caps on the board. The one on the right side in your picture looks possibly damaged. Hard to tell.
Thanks for the reply SBL. Here are the voltages you were asking about at the ARII and current my update.

+10.3 is at +10.18
- 5 is at --4.9
+12 is at +11.8

+22 is at +22.4
-22 is at -22.6

These are readings with game running.

It did not cut off today (knock on wood) and was on for over an hour and played several times before I shut it off.
 
Your issue is that burned up wire on the bridge rectifier.

10.18V is too low. You should be measuring 12-14V on the 10.3V test point, when things are healthy. Having it run high is normal, and necessary. That voltage is unregulated, and gets regulated by the AR. But the game board also uses the 10.3 for the power-on reset circuit on some games, so you can get intermittent resets when the 10.3 isn't perfectly healthy.

The slide-on connectors on the rectifier, as well as the fuse block, can be problematic on these after 40 years. Any place where two pieces of metal touch will oxidize after decades of contact and conduction of high current. When connections oxidize, they get resistive. And when they get resistive, they generate heat. And when metal heats up it causes more oxidation, which generates more heat, and the whole thing snowballs and the connector burns up.

The solution is to either replace the burned up connectors, or even better, cut them (and any burned wire) off and solder the wires directly to the bridge rectifier. Note that you will need to clean both surfaces (the wire, and the rectifier tab) in order to get solder to stick to them, as the surface metal will be oxidized. Sandpaper or a small file will work. And use quality solder, Kester 44 or 245.

Here's a thread with a similar problem, but on the fuse block, which is another place where it happens. But the solution is the same. Read this thread, and specifically note posts #17 and #18:


Also after you've fixed that, here's another thread with some additional general tips about Atari power systems:

 
Also, there is no need to replace the caps on AR boards. I post about this often here. You DO want to replace the 2N3055 bottlecap transistor on all AR's, but save your money and leave the original caps. Atari used excellent caps on their boards, and they are not the cause of power problems.

Replacing caps on AR's and Atari game boards is not necessary and won't fix problems. You're better off leaving those things original (preserving originality of the boards, and not hacking them up), and focusing on the things that actually do cause problems.
 
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