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

Troubleshooting Open Coils - Philco 84B
#1

Hi fellow members-
I am new to radio restoration but have been quickly learning about the process (although I have restored a couple of cars). I purchased a Philco 84B as my first project and am currently replacing the caps, resistors, and bakelites. I am slightly confused about troubleshooting the coils. For the oscillator and antenna coils, I get very low resistance values (2-8 Ohms) while checking continuity. I cannot locate the theoretical values and am hoping these are high enough values to indicate working coils(??)...does anyone know where can I locate these values for an 84? Also, the voice coil and output transformer shows OL so they appear dead. How do you guys figure out if these are good or need rewinding if you get values which are not OL or very high? Should I just assume they are OK and proceed with the rebuild? Thanks for your help-
-The schematic is attached
bdi


Attached Files
.pdf Philco84B Schematic.pdf Size: 107.45 KB  Downloads: 229
#2

Hi, welcome to the Phorum!

Exact resistances of the rf/if coils aren't important, as long as they aren't open. Your range of 2-8 sounds fine.

The field coil should measure 1140 ohms, the primary of the output transformer should be 400 ohms, and the voice coil .9 ohm. If any of those are substantially off or open, the radio isn't going to work. The speaker can be replaced with a modern one, and output transformer, and a resistor close to 1140 ohms at 20-25 watts or so. Hum may be increased without the field coil acting as a choke.


Good luck!

Will




Users browsing this thread: 2 Guest(s)
[-]
Recent Posts
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. ...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
Gilfillan Brothers Car Radio?
Hi everyone,  Special thanks to Joe Rossi for tracking down this obscure radio and thanks to others who took up the hun...Antipodal — 08:15 PM
trying to identify this wire type
Here's one source for your wire of many. Take care and BE HEALTHY! Gary P.S. Can't get the right color you need? I ...GarySP — 06:40 PM

[-]
Who's Online
There are currently 3137 online users. [Complete List]
» 2 Member(s) | 3135 Guest(s)
AvatarAvatar

>