Zenith Roundie Still Not Running

[bgadow]

I've never had it happen to me. There are sets that operate the damper sideways, but maybe that particular tube had a defect that caused a short to develop while on its side? Or just a plain bad tube? That should be among the more reliable tube chassis color sets, but then, even the best of them couldn't get near the track record of a solid state set.

[mattdavala]

On my Zenith roundie, a 24NC31 model I had a B+ power resistor that supplied B+(270V?) to the oscillator section and hortizontal output tube fail. It opened, killing the bias. Horz output tube died with the plate glowing red. My damper tube survived the ordeal. I know my issue was different from what you are experiencing, but I'd thought I'd throw this out there.

Ah, a key to me finding that resistor was that it also killed the B+ to the audio output section as well. Kind of odd, loosing HV and audio.

Replaced resistor and horz output tube got me working again.

Hope you get your running. Mine has been a daily watcher now for 4 years, with a few minor hicups one of which is told above. I did loose a damper tube in the 2nd year of opererating it. It failed peacefully, and replacing it brought my HV back. It has slight vertical jitteryness, and I know some caps in the vertical section will need replacing.

Lets hope when you get this sorted out that you'll have a worry-free Zenith roundie.
Good luck,
Matt Davala

[jstout66]

I love roundies, but as an everyday watcher,they are not reliable. I remember going on service calls when the roundies were about 15 years old, and it was not uncommon to have to make a house call 3 times a year. I remember those pieces of crap CTC-38's which would have been around 9 years old at the time and there were some we got stuck going out every few months.
Now granted, the roundies were the best the manufactures could put out at the time, and I would say a Zenith would be way more trouble free than a CTC-16, but they are what they are. Manufactures didn't want a bad rep, and which is why they strived for improvements until reaching solid state. To give these sets credit, they were often the ONLY set in a household, run 10+ hours a day, often in an un-airconditioned environment in the summer (which took a big toll).

I'm not out to "slam" tube sets, as I collect and love them as well, but one can not expect trouble-ree service, which for some, is part of the fun.

Good luck on yours, and hope it will be trouble-free for awhile.....