Mystery inductor- 37-660 - Printable Version
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Mystery inductor- 37-660 (/showthread.php?tid=555)
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: Mystery inductor- 37-660 (/showthread.php?tid=555)
Mystery inductor- 37-660 - AI2V - 01-11-2007
I'm not holding my breath waiting for an answer but here goes:
On the 37-660 IF amplifier (6K7), the suppressor grid (pin 5) has a coil to ground. Since my radio has been tampered with, this coil is missing. There is no component designation for this coil and the schematic is kind of blurry.
What is the purpose of this coil? I'm inclined to replace it with a couple of turns through a small ferrite ring or simply ground it and hope for no spurs or stray coupling. Can anyone tell me what the schematic is supposed to read?
- Chuck Schwark - 01-12-2007
That tertiary (TER-she-ary) winding is in the first IF transformer. If someone has removed the connections to it from the can, just ground the SUP grid.
See the GRN-YEL tracer and bare wire color designations on the schematic pointing to that winding?
Cannot remember the theory behind that circuit. Have to try to remember where I saw the explaination.
Mystery coil answer - AI2V - 01-12-2007
Thanks Chuck- I didn't look inside the IF can since the schematic gave me no hint. Since it's in the IF can it would seem that it might kill some sort of oscillation with negative feedback.
This is a terribly difficult radio to work on, especially in the oscillator section. I'm making test probes out of thin bus wire and had to put an LED on the end of wire to see anything. I'm even changing the tube sockets so that I will never have to go back into it. Tnx again for fast response and good info.
- Chuck Schwark - 01-12-2007
Yes, the schematic does not show the three coils within a dotted line or something to let you know that the coil is a winding in the can. Good luck.