Another set on the bench

[cdmarion]

Originally Posted by kx250rider

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

Charles and Zenith26kc20,
I decided to take your advise and put it in the dark, didn't see anything visual so I decided to give the HV cage and components a good cleaning, it was somewhat dusty in there. I sprayed everything down with contact cleaner and let it dry over night. I just fired it up and...........there's no cracks or pops or flashes, everything's back to normal.

thanks for your advise, every time I post something here I seem to always walk away with a little more knowledge and understanding on how these old TV's work and how to repair them. Thanks again

[earlyfilm]

Originally Posted by cdmarion

. . . . it was somewhat dusty in there. I sprayed everything down with contact cleaner and let it dry over night. I just fired it up and...........there's no cracks or pops or flashes, everything's back to normal.

Windex would probably have been a better choice for cleaning.

Many of the modern spray contact cleaners, even after drying, continue to attract dirt.

James.

[Phil Nelson]

For many cleaning jobs, I use plain old isopropyl alcohol (rubbing alcohol), which leaves no residue.

Cleaning is such a basic (and easy!) step that I included it in this article, "First Steps in Restoration."

http://antiqueradio.org/FirstStepsInRestoration.htm

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html