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

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

RF coil has resistor
#1

Hi All;
Can anyone tell me WHY the Primary coil of the RF transformer has a 10K Resistor accross it ?? The primary coil measures 38.6 ohms and the secondary coil measures 4.6 ohms.. The Primary coil is wound inside of the coil form in that cross hatch type of winding.. The Secondary coil is wound on the outside of the coil form..
The other set that has the same type of Mixer Tube 1C6, a Philco 39, which is a two band set against this which is a four band set.. The circuit is easier to follow on the two band set, and it looks like the Oscillator circuit is the same between the two, except that one is a four band set and the other a two band set..
THANK YOU Marty
#2

Please post schematic or link. Cold be limp attempt as a "fusister."
#3

Hi All;
Codefox, I would think that this is too old of a set to have a fusistor..
Here is the link for the Philco 34
http://www.nostalgiaair.org/Resources/185/M0013185.htm
And here for comparison here is the link for the Philco 39
http://www.nostalgiaair.org/Resources/265/M0013265.htm
My guess is for when the signal would be too strong, so as not to overload the RF transformer.. Or possibly some kind of Damping effect..
THANK YOU Marty
#4

That's often done to knock off the Q of the coil. Sometimes good RF selectivity is not a good thing since its variable across the band. And in a production environment it can create alignment headaches.
#5

Hi All;
Exray, Thank You, that is exactly what I needed to know.. I just fired up the set, with the Resistor disconnected on one side, just to see If it would make any difference.. I still just get a hum, my set doesn't know the Tune, either..
I will re attach it and try again..
I also will look at the Oscillator with my scope and see what I get..
Thank You Marty




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco Model 38-7: what caps & resistors do fail typically?
Since you stated earlier, you have a console 38-7XX.  They also had a 38-7T (table), and 38-7CS (chairside).  A very nic...GarySP — 01:18 PM
Part numbers to model cross
That I wouldn't know, but sometimes the radio document itself shows one, same as the capacitor cans' etc pinouts.morzh — 12:46 PM
Part numbers to model cross
Thank you morzh, that is exactly what I was looking for. Now , is there some where that shows pinouts for Philco power ...Jim Dutridge — 11:37 AM
Restoration of the Canadian General Electric A-87
Thanks for your help Michael. In fact, this video is only an intermediate result. Later I had to apply another tinting l...RadioSvit — 09:01 AM
Restoration of the Canadian General Electric A-87
Great job on the cabinet. PS. In the US notation, "kenotron" refers to specific type of tubes; we call re...morzh — 08:24 AM
Part numbers to model cross
This document has at least some tables of models and parts used. Example: Choke 32-7572, used in 604 radio. Search f...morzh — 08:19 AM
Restoration of the Canadian General Electric A-87
I also checked all the radio tubes on my Hickok 530 tube tester. The 5Z3 kenotron turned out to be faulty, all the other...RadioSvit — 08:02 AM
Restoration of the Canadian General Electric A-87
Well... While the varnish is drying up, I started repairing the chassis... Of course I started by replacing the pa...RadioSvit — 07:12 AM
Philco Model 38-7: what caps & resistors do fail typically?
Hello Martin, Welcome aboard our little community what great Model 38-7 Sincerely Richardradiorich — 12:30 AM
Philco Model 38-7: what caps & resistors do fail typically?
Welcome to the Phorum Martin. I count about 9 paper caps, the 3 electrolytic caps and 2-Y2 safety caps to replace th...RodB — 09:44 PM

[-]
Who's Online
There are currently 1424 online users. [Complete List]
» 1 Member(s) | 1423 Guest(s)
Avatar

>