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Dragging out an old nemisis-Philco 66 cathedral-SUCCESS
#43

I had some time to pull the o/c coil and I get continuity/ohms across each of the three windings (individually and from start to finish). I took the opportunity to do some re-tracing, replacing, and cleaning up. I replaced R15 and C14 (R15 is a 30K resistor, now). IF trimmers peak as before although it seems to me C19 has less of an impact on peaking ( this is the one with the mica cap across it), but the tone is clear and loud. I am able to hear a VERY weak tone at 1500KC and the tone responds to tweaking at C7 and C11 (the antenna trimmers). The tone also is specific to that part of the band (I only hear it right there. The radio also hums now at the extreme high end of the tuning scale (around 1200-1700) with and without the signal generator. I assume that when I hear the weak tone, I am using the signal generator as an oscillator?
Someone who has an abundance of free time might want to check my reading of the schematic for o/c. coil connections:

If I arbitrarily number the lugs on the o/c. coil starting with the lug to the right of the coil as viewed from under the chassis as #1, I have made the following connections:
lug #1: the lead that goes to pin 5 of the 6A7 and from there to C11.
lug #2: C14 connected to pin 3 of the 6A7 and one end of a 70 ohm resistor (the other end of the resistor is on lug #4).
lug #3: R10 connected to pin 6 of the 6A7 and a lead connected to C13.
lug #4: the 70 ohm resistor.
lug #5: a red lead connected to the band switch.

Charlie in San Antonio


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RE: Dragging out an old nemisis-Philco 66 cathedral - by ccomer1955 - 08-20-2014, 05:54 PM



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