wg7500 no color

mammyrat

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Sorry for the long read.
I have a wg 7500 27" in a Gaunlet Dark Legacy that wouldn't stay focused so I replaced the flyback, did a cap kit and reflowed any bad looking solders I could find. I cranked it up and adjusted the colors as per Randy Fromm's directions in The Big Blue Book. Looked great! Then it went out after about 10 minutes. I still had neck glow so I played with the connections and the chassis grounded out at the top left where there are no supports and the board bows down. The 5 amp fuse blew in the cabinet power supply.
At this point I took the chassis back out an looked it over again. The fuse was good. The 3 transistors on the neck board were kind of floppy, lifting the traces, so I jumped the traces and ran a small bead of silicone across all 3 to tie them together. I also noticed a component in the rear of the first picture that looks like a horz. width coil with out the adjustment. It was loose from its base. I also siliconed it. I put a piece of rubber under the sagging board corner and reinstalled it. The second picture is what I get now. No color. I tried adjusting the colors as before but no good. If I try to turn up a color the whole picture washes out with that color but the color never gets vivid. It always looks washed out. Same thing with my pattern generator connected. B+ is 130. video B+ is 198. Is it that coil thing? Or my silicone across the transistors?
 

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No colors (what looks like a black and white image) can often be caused by R811 going open on the main chassis. It's a 100K ohm resistor. Pull one side and verify with a meter.
 
After you said 100k and it was a 75k I checked the schematic, but I only could find a schematic for a 25" 7500. It said 1/2 watt 75k. But the main thing is the picture looks better than new. Thanks for your help. I might have never found that resistor open.
 
Yeh seems like some of them have 75k and some have 100k resistors. Anyway, R811 is the culprit.

Glad yours is now looking good!
 
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