Quote:
Originally Posted by cdmarion
I've pulled both tubes in the tuner and no change at all, I will say that when I turn the brightness all the way down it seems to get slightly worse. When you refer to power supply are you referring to HV? LV? or both?
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When you turn the brightness down, the HV goes up (and so does the B+ somewhat), so that's a BIG clue that it's power supply-related; HV or LV. 9 of 10 times, it's HV, but an internally arcing 5U4 could certainly do it too. I'm not familiar with that Admiral chassis #, so if it has a metal CRT, check for dirt around any and all mounts of the CRT, and check that the anode clip is secure at the front edge of the tube. Also check the HV cage and under the 1B3 socket, etc., for arcing. Sniff for any ozone smell, as that's a corona leak. As Zenith26kc20 said, you can turn the lights out and look around for blue corona beams, but usually corona doesn't cause popping. Usually it's arcing/snapping which causes that. Another trick is to aggravate the problem for testing purposes, by putting the chassis in a humid place and see if it gets worse or more obvious where it's arcing. Maybe in the garage or basement early in the morning, next to an open window in wet weather, etc. Some people will focus a humidifier toward the chassis, but I don't like that idea so well.
Charles