Wells Gardner 19K7302 (7300 Series) Color Issue

EagleTG

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I can't seem to figure this one out. Pictures first, and then some incessant rambling.

SWE1Monitor-01.jpg


SWE1Monitor-02.jpg


SWE1Monitor-03.jpg

I've already capped it, been over the board (component-level troubleshooting) a few quick times. Nothing is standing out as an issue. Neck board transistors all test similarly (diode DMM test all possible directions). The resistors next to the transistors also test in-spec.

Screen is the same after the cap kit as it was before.

It has a lot of blue, only some green and no red. The adjustment pots are cranked for green and red, I've tried moving the red and green cut-offs all the way in both directions with no significant change. I have the screen and/or brightness cranked in the pics to make sure it shows up (it's also sort-of dim). I'm leaning toward rejuvenation, and will try at least testing with a rejuvenator tomorrow.

Is there any chance that this is due to the chassis? I'm a bit astounded, this is really a relatively new monitor (compared to the 20+ year old ones I'm usually working on). I'm shocked this is having this level of issue already.

Anyone seen this issue on a Pinball 2000, Revenge From Mars, or Star Wars Episode I before? I'm also suspecting (nearly sure) this monitor has some EXTREME hours on it. I'm talking 24 hours a day for a significant period of time, so that could explain things if it does need a rejuve.

Thanks all!
 
Try swapping the blue wire to the neckboard with the red wire to the neckboard. See if it draws all the currently blue stuff in red:

a) If so, then your red gun in your tube is good, and your red circuit of your neckboard is good, but the red signal from the main chassis isn't coming up to the neckboard for some reason, perhaps because it's not coming into the monitor from the harness.

b) If not, but the normally red stuff is now blue, and the previously blue stuff is now gone or barely red, then you have either a red gun issue (rejuvenator) or a neckboard issue in the red circuit.

Repeat the process for green.

I recently worked on a K7000 model with no red, and had all parts and voltages present that I expected. Even so, the problem turned out to be a broken trace at the red input pin. What was interesting was that I was getting the same voltage readings on the red trace as the blue and green that were working, but the signal itself wasn't getting through telling it what to draw...
 
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