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Philco 38-12 no reception...
#3

This is what I would do. Connect your signal generator the grid cap of the 6A7 and the chassis. Set the generator to 470kc and align the two IF transformers. All three trimmers should have a pronounced peak if not check the winding for continuity.

Alter that is done measure the dc voltage on the 6A7's control grid (pin5) w/a high impedance volt meter (no vom). Should see some negative voltage there (a volt or 2) if the osc is running. You take a listen for it as Mike mention but may be nowhere near where it should be (470kc + the dial frequency). If not disconnect the wire connected to pin 1 of the osc coil and measure the resistance across the osc side of the tuning cap while rotating it from one end to the other. Should show no resistance at all (open). If not find the bent plate and straighten.

Check for hv on the screen grid of the 6A7 (pin4). If not osc coil is miss wired or open. Reverse the wires on pins 3 and 4 on the osc coil. Check #5 and 6 for tolerance. #6 can be substituted w/a 100mmfd cap.

GL

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
Philco 38-12 no reception... - by sdradioman - 11-18-2018, 10:48 AM
RE: Philco 38-12 no reception... - by morzh - 11-18-2018, 12:54 PM
RE: Philco 38-12 no reception... - by Radioroslyn - 11-18-2018, 02:14 PM



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