Blue issue with WG 19K4906

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I have an issue that just cropped up on my Jr Pacman monitor, it's like the blue knob is cranked to the max, see the attached pic. I tried a few things:

1) Tried wiggling the neckboard, pretty low tech but figured worth a try but that didn't do anything.

2) Used contact cleaner on all the color knobs. This monitor has red drive, green drive, red cutoff, green cutoff and blue cutoff knobs. I cleaned them all, rotated them through their full cycles, but that didn't do anything.

3) I tried setting the knobs to low settings, all that does is you then won't see the game playing anymore but the bright pattern is still there.

4) Tried the screen knob but same thing, if you turn it down the game will no longer be seen but the bright pattern is still there on screen.

5) Tried wiggling the signal cable in case it was making a bad connection, but that didn't do anything.

I'm a bit of a noob when it comes to repairing monitors (this would be my first) but I want to give it a try. Any suggestions would be appreciated!
 

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the blue transistor might be shorted, need to test it, or the blue gun might be shorted interanally and might need to be zapped. first two things I would look at.
 
Ok cool I'll start with the transistors. I looked at the schematic, there are three shown on the neck board, q401, q402, q403. Q403 is labeled "blue out", is that one you think may be the culprit?
 
Ok cool I'll start with the transistors. I looked at the schematic, there are three shown on the neck board, q401, q402, q403. Q403 is labeled "blue out", is that one you think may be the culprit?


the transistors that control blue on the main pcb are Q205, Q208 and also neck pcb there is Q403. if you need any i stock them. you can swap the blue one with the red or green corresponding transistor and if the problem goes to the other color you know that transistor was bad.
 
the transistors that control blue on the main pcb are Q205, Q208 and also neck pcb there is Q403. if you need any i stock them. you can swap the blue one with the red or green corresponding transistor and if the problem goes to the other color you know that transistor was bad.

Ok great, going to diagnose, I'll hit you up if I need parts, thanks!
 
Bumping this as I finally got around to testing the transistors on the neck board. Oddly the green and blue transistors on the neckboard test ok at near 600, but the red one which is q401 tests at near 900. Would that be considered bad? Noe sure why it would be the red one since it's showing blue on the monitor...but hey that's what the multi meter is showing.
 
One more bump, I got parts for this but before doing anything I decided to turn on the game and just leave it on for a while. When I checked it about 30 minutes later, the screen was perfectly fine and it's been fine ever since. I figure that means the various color related transistors are probably ok and instead maybe this is a cold solder joint someplace?
 
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