G07 monitor issue - static and jiggle

TheBasement

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I have a G07 monitor issue. During a gameday I noticed the monitor seemed to get static and then eventually no picture. It was playing blind. I turned the game off for 20 minutes and turned it back on again. The game came on for a period of time then the same thing.

The following is what I tried so far.

1. Replaced big blue
2. Cleaned the fuse holders
2. Did a full cap kit on the monitor. Even replaced the caps under the shield and put the shield back on.
3. Checked the resistors R314, R317, R303, R306. One of them was a 4.7k, I replaced it with the proper 390 Ohm.
4. Reflowed the connectors J1-J3 and E1-E6 (sync connectors)
5. Tried adjusting all the pots with no change.
6. Checked voltage off the game board and it read good. Even adjusted it from 5v to 5.15v with no change.
7. Measured B+ voltage and it measure 119.6V (120V)
8. Replaced fusible resistor FR401
9. Replaced X401 and X402 transistors
10. Replaced IC 501
10. Tried in another cab to eliminate game board, power supply and big blue.


This is a vertical game (DigDug) and with the monitor on its side it appears to have random staticy horizontal lines with very slight up/down jiggle.

I have tried to take a video of the issue with the monitor on its side. The video is very quick, but you can see the static if you bump the video to 480P. The single camera scan line is not part of the issue.

http://www.youtube.com/watch?v=fyUj24uPlDM

The picture and colors also look good except for the static and picture bounce.

Any help would be appreciated.
 
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Just an update. I just now replaced both IC501 and the very large filter cap that doesn't come in most cap kits. I've also replaced X401 and X402, along with FR401 in the vertical section. I also tested the monitor in another cab to remove any game board, big blue or power supply issues. I updated the top post to include what I just tried.


Still exactly the same. Uggh. Very pretty picture, with vertical jiggle and staticy horizontal lines going across the picture. The staticy horizontal lines are not in the same place in the monitor, they act like noise in a sense.

Any possible ideas?
 
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First: STOP.RANDOMLY.THROWING.PARTS.INTO.IT. If you're going to replace parts, make sure they're actually bad, first.

You did right by recapping and a new flyback, because this IS a G07 and that goes without saying on a monitor that's all original. But tossing random new parts can actually introduce new issues.

From the description, that this happens when it's been on for a while, and goes away after it's cooled down. This leads me to believe that it is some kind of thermal issue. Heat is causing a solder joint to expand, making a really crappy connection. It gets worse as it heats, and eventually stops making connection altogether.

Whenever I do a monitor rebuild, I resolder EVERY joint on the neckboard, the entire power supply section, and any other questionable solder joints. Examine everything closely.
 
First: STOP.RANDOMLY.THROWING.PARTS.INTO.IT. If you're going to replace parts, make sure they're actually bad, first.

You did right by recapping and a new flyback, because this IS a G07 and that goes without saying on a monitor that's all original. But tossing random new parts can actually introduce new issues.

From the description, that this happens when it's been on for a while, and goes away after it's cooled down. This leads me to believe that it is some kind of thermal issue. Heat is causing a solder joint to expand, making a really crappy connection. It gets worse as it heats, and eventually stops making connection altogether.

Whenever I do a monitor rebuild, I resolder EVERY joint on the neckboard, the entire power supply section, and any other questionable solder joints. Examine everything closely.

At this point the static and jiggle is immediate upon turning it on. I had not replaced the flyback yet. I will take your advice and go through again and check and touch up solder joints. However, I did not start randomly throwing parts in there. I started with a new cap kit, and when that didn't fix it I read up on threads and would try to replace another logical problem G07 part. I have a used donor chassis so it was simple to swap in another part. When that G07 problem part didn't fix it, I read some more until I came across another problem g07 part.

Do you think the flyback could cause the issue that is happening? I thought the flyback would either go out completely, or start to loose focus. I never read that they would act the way this monitor is.
 
A bit hard to tell from your video what is going on, but I have seen some weird jittery issues from a bad pot. Since you have a known good chassis you could swap out the pots?
 
If it's an original flyback, without question. It may not fix your issue, but it needs to be done.

Have you gone over the solder joints, yet?
 
I dont think it is a monitor issue, if you look carefully on the video the main part of the graphics goes black for a very brief moment, BUT the credit and round white graphics dont they stay on the screen just fine
, if it was the monitor everything would disapear in the brief outage to black. looks like gameboard to me but then you said thats been illiminated, but nothing else is going to cause black screen with credit and round still working
Andrew
 
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I seen in other posts that problem solder joints could happen in the 400 section. I took both of your advice, and swapped out all the pots for the main board from my donor chassis and hit all the solder joints in the 400 section with fresh solder.

SUCCESS!

I now have a rock steady picture. No screen static/noise, no jiggle, nice sharp colors. I wish I would have known which one was the culprit, but I happened to do both things while it was on the solder bench. I'm going to let it burn in the rest of the evening, and then on Tuesday I will probably let it do an all day burn in test when I work from home. I don't expect any problems, but just like to be sure before I button things up.

Thank you everyone.
 
I wish I would have known which one was the culprit, but I happened to do both things while it was on the solder bench.
If you were REALLY curious you could always throw the old pots back in it! :) If your problem shows back up you'll know 100% what your problem was. If it doesn't, you can put your spare pots back in your donor and know it was a bad solder joint in the 400 section.
That's what I'd do.....it would drive me nuts not to know! :)
 
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