04-04-2020, 07:48 AM
It may or may not have a direct Philco application as 500k is a very common value and it may have been made for a general replacement part. The fourth terminal is for part of a tone compensation circuit which boosts bass @ low volume levels.
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
