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

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

Philco model 38 code 121 not receiving signal.
#1

Hello everyone! 

I've been working on a Philco 38 farm radio with the code 121 version chassis. As you all may know this set uses a rather rare tube, the type 15 pentode as an autodyne converter. I am not deeply versed in autodyne converter circuits. I'm still a few shades green at this kind of stuff.
 To preface my work on this radio, I have recapped it and changed all of the resistors because they were out of tolerance. I did not touch any of the micas. I checked all voltages on the tubes and they are within spec. All tubes are good. I checked all coils and audio xfrmrs for continuity. They all passed. The tuning capacitor is a little
dirty but no plates are rubbing. I used the two radio method and verified the local oscillator is running. The driver and push-pull audio is working. I checked the band switch and it's good. When I touch the detector grid cap and I get a buzz. So the detector is working. When I touch the grid cap of the IF amp and I get a response, like the buzz plus static. When I touch the converter's grid cap I get static. I also touched the tuning cap stator terminal on the antenna side. That gives me static. When I take my finger off of the grid cap or the tuning cap stator, I get nothing. The antenna terminal gives no response when I touch it. It has a 4 foot length of wire with a little kit AM transmitter pumping out signal and the radio acts like it's not even there. Even though I checked the antenna coil could there still be an issue with it? Could it be the volume control? It uses the volume control to throttle the incoming signal. It's directly connected to the antenna coil. What am I missing?

 Any help would be appreciated.
Thank you.


Messages In This Thread
Philco model 38 code 121 not receiving signal. - by Stormlord5500 - 04-20-2025, 06:36 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
5U4 vs 5Z4 tubes
The pinout is the same but the 5U4 has a 3 amp filament, verses 2 amps or less on the 5Z4. I think that the pinout of a ...Arran — 12:04 AM
Philco 42-345 Restoration/Repair
By the way. osanders0311 Take a look here: Dial cord stringing Guides May be here you can fount correct string settin...Vlad95 — 11:15 PM
5U4 vs 5Z4 tubes
5U4 and 5Z4 almost identical. I think nothing happened if you left 5U4 instedad 5Z4 long time. Just heater current 5U4 ...Vlad95 — 11:02 PM
Philco 42-345 Restoration/Repair
Hello Vlad95 , Very Funny ! Sincerely Richardradiorich — 11:01 PM
Philco 42-345 Restoration/Repair
RodB You are European yourself   :evil: I'm Canadian for the last 30 years  :snowman: But not Yankee  :lol: Vlad95 — 10:49 PM
Philco 42-345 Restoration/Repair
The band switch selects different oscillator coils for the band selected. I would look for a bad connection in the switc...RodB — 10:31 PM
Philco 42-345 Restoration/Repair
Hang in there...PaulPaul Philco322 — 09:30 PM
Philco 42-345 Restoration/Repair
The thrill is gone again, thought I was close to being done with it. Well Friday it was receiving broadcast, Saturday mo...osanders0311 — 07:47 PM
Help with Supreme 599
Iam getting closer to fixing it. I bumped Up the tranny voltage to get 5v on the 80 tube. I gan get the needle to move ...daveone23 — 03:41 PM
Philco 42-345 Restoration/Repair
Hello RodB, Checking my previous post I realized you're the one with the 42-340. I replaced the string for the tuning...osanders0311 — 03:12 PM

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

>