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

38 116 RF tube
#1

I gave a 38 116 to my cousin. I have replaced all caps and out of tolerance resistors.  It played well over a year.

Recently it died so I drove out to see him over the weekend. 

Cheking tubes, the RF rube was dead. I also had no voltage on the plates of the first audio and oscillator (6N7 and 6A8). All components there were correct and not shorted or open where appropriate.   While we wait for a new tube, would a dead RF tube cause the radio to go silent?  I think so but would like an expert opinion to help with troubleshooting if that's not it.

Thanks 
Steve
#2

You might check the resistor numbered 117 on the schematic. This is a chassis mounted wirewound resistor that drops plate voltage to the oscillator and AF tubes. If it opens you will lose plate voltage to the affected tubes.

Also filter cap 70A could be shorted, causing resistor 117 to open.
#3

Thanks. I was thinking that.  I'll check that resistor next trip out there. I need to bring an iron and some tools with me then.

The filter caps are good. All the voltages were close and all they are all new.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Zenith H725
Here's what the inside of AM IFT2 looked like, and the other pic shows the discs I made to take place of the mica and ke...EdHolland — 07:40 PM
Zenith H725
IF2 will need replacement caps. The arcing was severe enough that the mica is pitted and holed where the HT flashed over...EdHolland — 04:04 PM
My Philco 37-116 Restore
Measuring from center tap like the tube voltages show. Cap 127 is isolated from ground. Cap 127 shown in upper left of p...dconant — 08:05 AM
My Philco 37-116 Restore
Are you measuring relative to the centertap or the GND?morzh — 11:57 PM
Philco 610B oscillator wiring
Still not clear on the wiring interface between the 6A7 and oscillator. After refering to the available schematics and s...Tubester — 07:18 PM
Refinishing Ideas
My 37-116 code 121 is the best sounding radio i have...a daily driver. Since we are talking about "changes". ...poulsbobill — 07:18 PM
My Philco 37-116 Restore
Hello, I finally got brave enough to take the cans off the Expander Unit. Got the grid cap wires replaced and back toget...dconant — 06:50 PM
Zenith H725
I got into the first AM IF can today, and found its mica was cracked. Amazing that it was still working. This one makes ...EdHolland — 06:10 PM
Philco model #20
AHH HA , I got it and can’t thank you fellows enough , when I changed the capacitors I took the advice and did not unsol...onlyrick — 02:24 PM
Zenith H725
Hello Ed, yes, I like letting projects run for few days to make sure they don't start acting up . Sincerely Richardradiorich — 01:03 PM

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

>