Quote:
Originally Posted by init4fun
Hi Ben , I'm hoping for all kinds of chassis shots here when you get into it ! There is something VERY special to me about a TV that has only octals and no 7 or 9 pin "modern" tubes , I really like the prehistoric nature of sets using the big tubes . So , does it have a mains derived HV or is there some type of RF HV circuit in there ?
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This set uses mains derived "brute force" HV. Very pre-war in nature, despite being constructed no earlier than May of 1948 when channel one was dropped by the FCC.
It does in fact use some 7 pin miniature tubes. It uses two 6AU6s and a 9002 in the tuner, and a 6AL5 in the audio discriminator. The original 1947 and early 1948 kits didn't have the later 12 channel tuner, using a 3 or 5 channel tuner depending on when the kit was built. They also used slope detection of the sound carrier, as opposed to the true FM discriminator circuit in my kit.
There are a number of octal tubes missing from my set, so I'm going to have to sit down with a schematic and determine whether my set uses the "late-model" horizontal sweep circuit or the original version from 1947. If it does in fact use the late version, then I think I can safely say this is probably among the last of Transvision's 7 inch kits sold and constructed. I can't find any reference to 7 inchers with the 7EP4 post 1949. The original JAN tubes still in this set all have 1949 or 1948 datecodes.