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Troubleshooting a WG 25k7191 no picture blowing fuse
joej85a:
--- Quote from: princess prin prin on March 26, 2020, 03:22:25 pm ---C36 and C69 are correct for 25". The HOT has been replaced with a different type (still with damper diode, hopefully compatible enough) and the vertical board can stay (I don't know if it's indeed for pincushion without seeing it). The neckboard can be swapped.
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Okay, so I did swap the neckboard and viola! The tube came to life. Got some serious adjustment and picture issues but I am dialing it it. Picture is great vertically, it is a little short horizontally. The biggest thing i noticed was no Red color, and a serious "bloom" in the middle but only when there is a white object there, like the big golf ball. Ill try to get a picture of it up.
But hey I consider that a win, nothing blew up! Im look forward to trying to get this other board with all the new parts in it and going.
joej85a:
The saga continues.
So I removed Q1 and Q201 from the Red circuit and swapped them with the same from the green circuit to test to see if that is where the failure is. Unfortunately still no red. Solder joints look good, no broken traces that I see. Right now, looking like the tube, which stinks.
I did mess with the red pots on the neckboard and turned them all the way up and could kinda get a rust red all over the screen. Like a faint background. Anyone know if that is a particular indicator?
Off to start researching a tube swap!
grantspain:
could be gun, momentary short the red gun to ground- that will prove tube
joej85a:
--- Quote from: grantspain on March 27, 2020, 05:19:28 am ---could be gun, momentary short the red gun to ground- that will prove tube
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Thanks Grantspain, I have read about the "ground the red gun" but honestly I am uncertain what to take to ground. Any clarification would be very much appreciated.
Back to Project 1: got the replacement capacitors in today and got them installed to the original board. Looking good. Also got the new STR30130 in and installed. Finally getting 130vdc with Prin's isolated bulb test. Nice! I am now moving to the expanded traditional bulb test that brings in more components. Fingers crossed, I will post the results!
joej85a:
Woohoo getting 130vdc with full bulb test. Going to reinstall the new HOT and see what happens. Fingers crossed again.