Space Duel - green vectors flicker?

Rat

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Have only had my SD cocktail a short time and mostly it's OK but I would like to have it perfect.

The issue is the green vectors flicker on and off. Seems to possibly be slightly more stable after its been on awhile, but will still happen occasionally.

The seller put a new caps kit throughout so it's not that.

I'm thinking it's loose wiring, I have reseated all the plugs. At one stage I did find a green wire going to a plug that made the worse, green disappeared if moved about. I have reseated and checked that, but I had trouble getting the plug out of the metal holder on the side of the cab, so I have not been able to re-solder that yet. Not sure that would help as it looks fine.

So should I persist with trying to remove this plug risking breaking the brittle plastic, or check other things?

Perhaps there is a voltage pot I could adjust or something?

I'm a noob with my multimeter but if you hold my hand and show me pictures I will have a try :D

I have downloaded the manual and had a quick read, but now I'm at work using my phone for a few days. So I can't take pics of the plug ATM. Just hoping for a quick head start on my trouble shooting when I get home. Any help greatly appreciated.
 
Could be anything in that color circuit from the op amp(s) on the board to the color amp on the monitor. Verify all connectors/wiring first, then if that doesn't do it its time to get out the schematics. It makes things easier to find a fluctuating voltage when you use a test screen instead of the attract mode. As long as the text is white all color outputs should remain static.

There's also digital color intensity circuitry on the board that could be flaky.
 
Yeah fairly sure it looks like the one in the fourth pic down, the plug on the bottom left.

The top connector plug on mine is held in a metal bracket screwed to the cab. The screws are difficult to get to, and the plug is stuck in the bracket so I have not been able to get it out to view properly or work on. Not sure what to do with this type of plug, probably just remove the offending wire and resolder it to the pin inside the plug. I think the pins can be pushed out to do that.

Might try spraying a little CRC on the plug to see if I can remove it then.
 
I checked all my connectors, they seemed good and re-seating them made no difference. I also could not get the wire and plug that I had suspected before to change the vectors when I fiddled with it, that might have been just co-incidence before?

I was starting to think it wasn't connectors at all and that I was going to have to delve into brain busting troubleshooting.

But then I decided to check a couple of plugs that plug into the board behind the monitor just one more time. Luck was with me and when I pressed on one of them the vectors became brighter. I had done that with that plug before without result, and pulled and re-seated that plug also, just lucky that I tried again.

So I pulled it again and had a good look at the wiring, it looked good, then I remembered I had some Contact Cleaner Lubricant Spray and I gave the plug a spray.

YAY that WORKED I have played about 10 games since spread over three different sessions and the picture has been perfect :D

(I did have one random hard reset that it has never done before and has not done since, so I'm going to ignore)

I have not bothered taking a pic of the plug as I don't really think it would be that useful to others who may read the the thread, but if anyone does want to see it just ask.

I probably jumped the gun even posting this thread at all, I should have spent more time trouble shooting it myself before posting. So thanks to those who offered advice, and sorry it was so trivial. I wanted it fixed ASAP as I'm hosting a games night meet in a couple of weeks and I didn't want one of my star attractions blinking, I'm a happy boy now :)
 
Great result

Yes it would be useful for all the vector heads on this forum to see a pic of the offender, if at all possible, please :D





I checked all my connectors, they seemed good and re-seating them made no difference. I also could not get the wire and plug that I had suspected before to change the vectors when I fiddled with it, that might have been just co-incidence before?

I was starting to think it wasn't connectors at all and that I was going to have to delve into brain busting troubleshooting.

But then I decided to check a couple of plugs that plug into the board behind the monitor just one more time. Luck was with me and when I pressed on one of them the vectors became brighter. I had done that with that plug before without result, and pulled and re-seated that plug also, just lucky that I tried again.

So I pulled it again and had a good look at the wiring, it looked good, then I remembered I had some Contact Cleaner Lubricant Spray and I gave the plug a spray.

YAY that WORKED I have played about 10 games since spread over three different sessions and the picture has been perfect :D

(I did have one random hard reset that it has never done before and has not done since, so I'm going to ignore)

I have not bothered taking a pic of the plug as I don't really think it would be that useful to others who may read the the thread, but if anyone does want to see it just ask.

I probably jumped the gun even posting this thread at all, I should have spent more time trouble shooting it myself before posting. So thanks to those who offered advice, and sorry it was so trivial. I wanted it fixed ASAP as I'm hosting a games night meet in a couple of weeks and I didn't want one of my star attractions blinking, I'm a happy boy now :)
 
Here is a picture of the board on the wall of the cab behind the neck of the monitor. Pen pointing at offending plug, that seems to control the intensity of the vectors, from what I have read they have 6 different levels of intensity. I think my problem was that some of the vectors (or all) were flickering or changing intensity levels, sometimes they would stay as a dull, weak line.
 

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Thats the yoke plug.. It goes to the yoke on the tube, which basically moves the electron beam around..In theory has nothing to do with vector brightness, other then if its not plugged in, then the spot killer comes on. Id guess youve wiggled something that fixed a bad connection somewhere else. The only thing on that board that would have anything to do with brightness is the spot killer, and it should affect all colors. Id pull that board and the neck board and clean all the connections, check wires and solder joints. And rebuild that sucker if you havent already!

Andrew
 
Thats the yoke plug.. It goes to the yoke on the tube, which basically moves the electron beam around..In theory has nothing to do with vector brightness, other then if its not plugged in, then the spot killer comes on. Id guess youve wiggled something that fixed a bad connection somewhere else. The only thing on that board that would have anything to do with brightness is the spot killer, and it should affect all colors. Id pull that board and the neck board and clean all the connections, check wires and solder joints. And rebuild that sucker if you havent already!

Andrew

I would be doing this as well to alleviate any future problems.
 
OK thanks for that advice, it has had all the caps replaced. But I will get round to doing a thorough clean and inspection in the near future.
 
It started playing up again so I decided to bite the bullet and pull the board out for an inspection before the meet, wanted to get it perfect if I possibly could.

Had a good look at all the plug solder joints and found that they had been reflowed already, a good job was done of it and they all looked undamaged. I would guess that a previous owner had this problem before and tried to fix it by doing that. Perhaps they then gave up and that is why I now have the machine?

Hmmmm, OK probably not that then, there is still a very small chance that one of the solder joints has a hairline crack that I didn't notice, but I don't think this is the cause.

Anyway I was still convinced that the plugs not being a tight fit was the cause. This would explain why it worked well after I had reseated the plugs, but then after I hammered the buttons for awhile they jiggled just loose enough to cause my issue again.

So I thought for awhile about how I could better secure them, cable ties, but it took me awhile to work out how to do that effectively. Then it suddenly became obvious, I wrapped the cable ties around the plugs pulling the plug retainer lip into the plug to secure them as they would have been when the plastic was new. Worked a treat and I have played for two days now, a few hours worth of play with no green dimming or flicker AT ALL.

Fingers still crossed, but I think I'm safe to say cable ties have saved the day :D

Pic of cable ties attached, I will clip the ends off when I'm sure they are adjusted right, and the bits of sticky tape with numbers is me making sure I plugged everything back in right after replacing the board.
 

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Id pull that board and the neck board and clean all the connections, check wires and solder joints. And rebuild that sucker if you havent already!

Andrew

OK turns out this suggestion was the winner thanks :) the cable tie attempt was NOT a fix at all and only fooled me because it had been an intermittent problem. I really was only trying anything I could to not have to remove the neckboard in case I damaged something.

Anyway when it started playing up again I decided I would have to have a look at it. It was very fiddly to get to some of the earth leads, but finally got it out for a good look under the microscope. This board had been reflowed in places also, but it wasn't as good a job as the other board. So I tidied up the solder on a few pins that looked like potential trouble. Then I noticed that there was a diode that had one leg that was hardly even connected to the rear of the PCB at all, it was attached, but only just, I'm fairly sure this was the culprit now.

Refitted and cranked up and the green vectors looked thicker and brighter than ever, I hoped it wasn't just wishful thinking. But it has been playing rock solid now for three days, I have played for hours, beat my high score, and I still think the green is brighter and stronger than ever.

FIXED :D
 
OK turns out this suggestion was the winner thanks :) the cable tie attempt was NOT a fix at all and only fooled me because it had been an intermittent problem. I really was only trying anything I could to not have to remove the neckboard in case I damaged something.

Anyway when it started playing up again I decided I would have to have a look at it. It was very fiddly to get to some of the earth leads, but finally got it out for a good look under the microscope. This board had been reflowed in places also, but it wasn't as good a job as the other board. So I tidied up the solder on a few pins that looked like potential trouble. Then I noticed that there was a diode that had one leg that was hardly even connected to the rear of the PCB at all, it was attached, but only just, I'm fairly sure this was the culprit now.

Refitted and cranked up and the green vectors looked thicker and brighter than ever, I hoped it wasn't just wishful thinking. But it has been playing rock solid now for three days, I have played for hours, beat my high score, and I still think the green is brighter and stronger than ever.

FIXED :D

Noice! . . . .
 
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