Quote:
Originally Posted by tubesrule
Nick, it's disappointing to hear the set does not have the CPA switch and may be too far modified from it's origins to put it back.
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Regardless, it's a very interesting chassis to look at even if it never works. It's a great historical piece, since it's obvious they were trying different things with it. It has chassis stampings labeled 'CPA' and 'DELAY', and there are a pair of 12AU7's not connected to anything that look as if they may have had something to do with CPA at some point but now serve no purpose. Looking at the local oscillator, it has a pair of phase shifting networks on it's output which then go directly to the R-Y and B-Y demodulators. It resembles an NTSC circuit more than anything else, so that's what I'm putting my money on. Still not clear if it's I/Q, but since it was what they eventually decided on it's highly probable. Nailing down the years it was worked on would help, but there are no identifying marks on it.