The PHILCO Phorum

One thing I've noticed Philco doing is winding a coil over a tubular capacitor. I've seen it in the 46-350 (L1/C26) and also in the 48-475 (no coil #/C317). Perhaps this is done in other models as well. Question is: How critical is this combination, i.e., does the cap act only as a form for the coil, or is the design such that it relies on the proximity of the coil to the ground shield of the cap? If the latter, is there a secret to recapping this combination?

Hi

This cap-coil combination was used in many Philco receivers, chiefly right after the war. It serves as an IF trap in the B- circuit. Chuck has an extensive write-up on this subject on his website:

http://www.philcorepairbench.com/tips/svctip37.htm

In practice, you can usually eliminate the cap-coil combo by replacing the capacitor itself, leaving out the coil, with no ill effects. However, you may retain the coil if you wish.