Quote:
Originally posted by peverett
What manufactures did with PC boards seemed to be all over the map in the 1960s. Zenith did not use them at all. RCA used them for the lower power tubes, such as the IF, Video AMP etc. while mounting higher power tubes on the chassis. GE (and sometimes Philco) placed every tube on a PC board-Bad idea.
I did work on a RCA roundie color TV with a carbon trace problem on the PC board once, but their idea of using the PC board for the low power tubes seemed to work pretty well. In fact I have two 1962 portable B&W RCA tvs built this way that I watch regularly.
However, I have some small GE B&W sets and only could barely restore two out of five of these as the Horizontal output tubes had charcoaled all of the PC boards. I am sure this caused a lot of headaches even when these sets were much newer.
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In the '70s I had a 1964-vintage Sears Silvertone 21" roundie (one of my neighbors in my hometown was throwing it out, which is how I got it). The chassis bore a striking resemblance to RCA's CTC12 (although the set was actually built by Warwick Electronics). Would you believe that nine years later (three years after I got it in '70), the video-output tube socket broke out of the video circuit board?
So much for circuit boards being made to last. I've been wary of sets with circuit boards (especially those cheap Japanese-built portables--I've had a few in my time--with the entire set except the tuner and control cluster, including the flyback, horizontal-output and damper, etc. on one large PC board) for years. These sets are extremely difficult to work on; if a tube socket breaks or the flyback cracks the board, etc. the set usually gets put out with the trash, and if the CRT goes--same thing. These sets were built cheaply to sell just as cheaply. The only circuit-board set I ever owned that lasted me more than a year or two (aside from my two color sets I have now and two 13" color sets I bought in the '80s) was a Zenith solid-state 12-inch b&w portable I bought new in 1978. That set lasted 22 years without a bit of circuit trouble and had a beautiful picture all that time; in fact, the only problem I ever had with it was when the detent mechanism of the UHF tuner broke and jammed the tuner on one channel. The same thing happened with my first new color TV, a 1980-model Zenith 13", but again, it never developed any kind of circuit problems; same with an early-'80s vintage Zenith with electronic tuning.