Quote:
Originally Posted by earlyfilm
The RCA printed boards and Zenith crimped-cone connectors reminded me of a conversation over 50 years ago, and I have a question that is like remembering a joke, but forgetting the punch line.
Back sometime between 1957-1959, an older non-working B&W TV set with a brand name unfamiliar to me came into the shop. My boss took one look at the set, muttered a cuss word, and he told me to not to start repairing the set, but pull the three IF tubes and use a vector adapter and measuring from the cathode, to see if any of the IF tubes had plate voltage on the control grids, and to confirm that there was plate voltage on all the plates.
I followed his odd instructions, and told him that the voltages were normal for pulled tubes. He told me that it then was OK to work on the set.
Dumbfounded, I asked him what was the problem this set had and he replied with the story:
RCA had a bright idea to eliminate the need for separate IF transformers in TV and designed a wide band TV circuit that used printed IF transformers. RCA never used these circuit boards in sets they made, but sold or licensed them to this company, who used them. Almost all started failing within a year or two. Between the cost of the warranty failures and the bad publicity from the out of warranty failures insured the demise of the company. In addition to this problem, the shields for the printed transformers often had cold soldered connections and to be sure I tapped them while watching the picture when I got the set working.
Which TV manufacturer got shafted by these bad circuit boards?
All I can remember about the set was it was a good looking walnut console in rather clean condition from a family that did not smoke and the chassis was made from very thin punched steel.
James
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IIRC, RCA did use those IF boards.
The set you worked on was probably a Stewart Warner. I think Stromberg Carlson used them, as well.
I never had a problem with them, but a friend had a freebee Stewart Warner, where the IF strip was all butchered up and wasn't worth the time to repair.