05-11-2020, 08:55 PM
After review the diagram some more I thinking the sec of 28 isn't really a feedback winding but it does act as a plate load for the triode section of the hexode mixer. So you are correct that if the winding was open or had some type of defect the PB would not work. With that in mind it could be replace with a rf choke. It would allow a load for the plate and present the rf osc signal to #32 which block the dc voltage and passes signal. The pri of #28 is connected to the grid circuit thru a bunch of switches and the other end of #28 is connected to the plate signal thru 32 and a bunch of switch.
Philco used a 2 or 2.5MH chokes in some of their '41 models.
Philco used a 2 or 2.5MH chokes in some of their '41 models.
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
