Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Open rf choke in Model 48-482
#1

This is my first post, although I have been using the Philco Phorum as an information source to assist in radio restorations for some time. Thanks to all contributors.

I restored a Philco Model 48-482 about a year ago and it has been playing very well until recently when reception problems began on the FM band. At first it an intermittant problem and eventually became no reception at all.

By following the Riders trouble shooting instructions I have found that the L300 rf osc choke (part #32-3352) associated with the FM1000 tube is open. When I bridge the choke with a piece of wire the FM band functions but the fidelity is not good. Is it possible to repair this part? If not what can I use as a replacement. Thanks for your help.
#2

After looking and scratch my head it looks like a quadrature detector. The cathode,control grid, and second grid act as an oscillator at the IF frequency 9.1 mc. L300 needs the be resonant at 9.1 to cause the oscillator to operate. I suspect that when you wired in your replacement it caused the FM1000 to conduct but not oscillate.
Terry
#3

Can you post or send me a pic of??
Terry
#4

Thanks for the information Terry. I searched the Phorum one more time and found someone else had the same problem with the RF choke opening up. Their solution to the problem was melting the wax off of the choke and repairing the break in the wiring. I tried the same thing and was also lucky in that the break in the choke wire was located where it could be repaired. After making the repair and recoating the choke with wax I reinstalled the choke and now the radio is playing perfectly on the FM band. Thanks again for responding.
#5

Great!!! Now I can sleep again!!
Terry




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 16B Parts
Thanks for the reply. Unfortunately the radio was removed before bidding was over so I didn't get a chance to bid.dconant — 04:10 PM
Philco 16B Parts
Hi Dan, Mike is correct, there's a lot of painted stuff on the chassis but it looks pretty good. The sm is all there,sp...Radioroslyn — 03:50 PM
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
Hi Cap'n Clock, Unfortunately, I do not have this radio.  This is a shame because this should be a good performer.  2A...captainclock1988 — 03:43 PM
Philco 42-390, code 121 speaker
Using a 5W  1.5k  ceramic resistor in place of the field coil and using a 4 ohm PM speaker, I was able to bring the radi...Stevelog — 02:57 PM
Philco 60 Squealing
I have taken out the 2nd IF and found a problem or not. I believe the coils are litz wire. There is a very small strand ...dconant — 02:13 PM
Philco 6K7
I am restoring a Philco 37-60. The am reception is very good, but the shortwave is very weak. Run 6 Philco removes the g...bobbyd1200 — 01:35 PM
1930s Stromberg-Carlson Tombstone Radio need help identifying model number
Hi Cap'n Clock, Unfortunately, I do not have this radio.  This is a shame because this should be a good performer.  2A5...MrFixr55 — 06:48 AM
American Bosch Model 802 auto radio
I think it would come under either American Bosch or United American Bosch. American Bosch made sets for the American We...Arran — 05:53 AM
trying to identify this wire type
Thanks to all for the feedback. As Arran said, it is probably an older replacement and yes it has a grid cap so I will ...georgetownjohn — 09:32 PM
trying to identify this wire type
It's possible that the red wire, actually a grid cap lead, is a very old replacement, I can't remember seeing a pre 1939...Arran — 09:18 PM

[-]
Who's Online
There are currently 5290 online users. [Complete List]
» 1 Member(s) | 5289 Guest(s)
Avatar

>