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Old 03-22-2010, 08:34 PM
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Jeffhs Jeffhs is offline
<----Zenith C845
 
Join Date: Feb 2003
Location: Fairport Harbor, Ohio (near Lake Erie)
Posts: 4,035
If the sound goes off every hour, and turning the set on and off always brings it back, my best guess would have to be that there is an intermittent that only acts up after the set has been playing awhile. However, this is only a guess, and since you can always get the sound to come on again by rapidly switching the power on and off, it probably isn't a very good guess at that. I'd check the sound module for cold solder joints, cracks in the printed wiring board (this sounds like one of Zenith's modular chassis) and other things that would show up only after the set has been on and running for an appreciable length of time. This is called a "thermal" intermittent and can be the very dickens of a thing to find, but from your description (except for being able to get the sound back by switching the set on and off), it sounds like that may well be the cause of your sound trouble. You may be "shocking" a bad component or connection on the sound module into temporary normal operation by your rapid power switching, but the key word is "temporary" since the sound will disappear again in another hour.

Not being any kind of expert on Zenith TVs, especially the solid-state ones of the '70s through the nineties, however (most of my experience has been and is with older Zenith tube-type radios), I will step aside at this point and let the Zenith TV experts here like zenithfan1 and drh4683 guide you further.

Good luck. Those older Zenith TVs were great performers in their day, and can be again with proper servicing. I had a great-uncle who replaced the RCA color television chassis in a 3-way console in his living room with a 1974 19" Zenith Chromacolor II, IIRC; the set worked beautifully until he died in 1987. My great-aunt then got rid of the old console, bought a Zenith System 3 console and kept the latter from '87 until she died some 15 years later.

In its day (decades before Goldstar made a mockery of their name and reputation), Zenith was an excellent brand of TV; I had several of their black-and-white sets and a couple of their solid-state color portables, and had excellent results from all of them. The two Zenith color sets lasted 19 and 16 years, repectively, and were still working when I gave them up shortly before I moved to my apartment in 1999. I also had a 12" Zenith b&w solid-state portable that lasted 22 years and was still going strong when I got rid of it ten years ago. I would have kept it, goodness knows I should have, but my apartment was and is just too small for three TVs; I brought one Zenith color set with me when I moved here and bought a brand-new RCA CTC185 at almost the same time, so the li'l 12-incher had to go. I hated to part with that set and my two 13-inch portable color sets, but moving from a three-bedroom house with a basement to a one-bedroom apartment means lots of downsizing, as I'm sure many of you know.
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Jeff, WB8NHV

Collecting, restoring and enjoying vintage Zenith radios since 2002

Zenith. Gone, but not forgotten.
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