Zenith Roundie Changes, Improvements, & Issues

[Jeffhs]

Originally Posted by trinescope

The Zenith vertical output transformers have a habit of developing shorts between the primary and one of the convergence windings, which essentially shorts the vertical stage B+ to ground through all the low resistance parts in the convergence circuits. For whatever reason the insulation on the wires as well as the paper tape materials break down. I had this failure on a CTC-5 as well, due to the way the windings were done it allowed all four secondaries to short to B+, which smoked all three DC convergence adjustment pots. I have already rewound that transformer, and is working, just need to find a working substitute for the three pots (100 ohm with a tap at 75%).

I am amazed Zenith color TVs even had this problem (shorts in the vertical output transformer) in the first place. I would have thought Zenith's quality control department would have been aware of this and corrected the problem long before it reached this point. Zenith, after all, was one of America's best radio and TV makes (if not the best, hands down) since the company's founding in 1918. Why they would allow defective components such as vertical output transformers knowingly get into their televisions (unless it was a one-time fluke) is beyond me. I always thought their QC (quality control) division would have caught this problem before it became anywhere near this serious. If Zenith were not already as well-known a company as it was, I would think a problem like this would have put the heck of a dent in its reputation. Zenith's decades-old slogan, after all, was "the quality goes in before the name goes on"; a problem like this would have all but ruined the integrity of that slogan (and put the company out of business for good) in no time flat.