Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Philco 46-480 Replacing Field Coil w/ Perm Mag (I know I know)
#53

Good Sleuthing RetroRev. As a kid, one of the many dumb things I did on purpose was to attempt to fix Heathkit projects that never worked when someone else built them. Sometimes, another set of eyes will solve the problem. Unfortunately, for this radio, you are the other eyes! Give yourself a pat on the back when you get this going.

BTW, if you are using a PM speaker and did not "up" the capacitance of the filters, you may get a low hum, even with the volume control down. This is because in a speaker employing a field coil, there is a "hum bucking coil" in series with the speaker voice coil. This is engineered to cancel power supply hum by being wound in "reverse polarity" (maybe not the best description but should work) to the direction of the field coil. In addition, the field coil acts as a "choke", giving resistance to the "Pulsating DC" ripple in the power supply that a plain ol' dropping resistor does not provide.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
RE: Philco 46-480 Replacing Field Coil w/ Perm Mag (I know I know) - by MrFixr55 - 10-13-2022, 04:46 PM



Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM
Preliminary work on wife's Silvertone 2014
Hello roy, that great news glad it worked out for you !! Sincerely Richardradiorich — 10:50 PM
Preliminary work on wife's Silvertone 2014
Safety caps arrived today.  Soldered one in and had a successful first power-up.  No magic smoke escaped and it tunes in...glyphmon — 09:53 PM

[-]
Who's Online
There are currently no members online.

>