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Old 12-07-2015, 07:36 AM
Kamakiri's Avatar
Kamakiri Kamakiri is offline
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Join Date: Jun 2002
Location: Buffalo, New York
Posts: 5,109
Working on an Admiral 20X12

Just finished a recap of an Admiral 20X12. I'll start by saying that the chassis on this thing was REALLY rusty. It sat on a basement floor for God knows how many decades. The only reason I decided to tackle it is, well, I felt sorry for it. You know how it goes

Anyway, the Sams for this set leaves a lot to be desired, and here's what I've got.....

No reception, no static, no HV. The horizontal oscillator isn't running, but the vertical is. Okay, so time to start testing resistances. My problem is on pin 4 of the 6BG6. Totally open. It seems that pin 4 is simply a tie point going from the power switch to the transformer.

I checked resistances at the 5U4, and they're in the ballpark, but the moment I put my probe on the tube pin, the resistance will start climbing and climbing until I remove the probe, when the resistance starts to decrease, eventually back to the correct value.

I may be wrong, but I'm starting to put two and two together and think that I may have a bad winding in the transformer. The only other thing that is shown in the Sams that is NOT on the set is a 270K Ohm resistor between the AC line and the transformer.

Whatcha think?
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