Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x


Philco 39-7 issues
#23

Jeff, NO!! you are NOT wasting your time! Not only are you restoring history, you are gaining troubleshooting skills, so keep at it, and you will get success. Worst case scenario, my usual statement, install a "Radio / Aux Input switch" and jack and you can pipe old time radio through it!

You stated that you moved Cap # 26 negative lead to R24, the important thing is to ensure that you connect the negative lead to the JUNCTION of Resistor #26, Resistor #19 AND the center tap of the transformer HV secondary.

This should not have caused the resistor to burn. Having Cap #26 connected to the chassis would have increased the draw through Resistor #24.

Definitely replace both Resistors 23 and 24 with a minimum of 2 watt resistors.

Next step is to touch the grid cap of the IF tube and determine if there is noise from doing so, especially hum or continued static. If so, that tells us that stage is working. If not, troubleshoot in a similar manner as the Audio stage. Measure Plate, "Grid Plate" voltage on the convertor (1st detector) tube, the 6A7.

If you do not have one, obtain a copy of the RCA Receiving Tube Manual RC13 from 1937. Here is a link to the World Radio History website, a great resource!

https://www.worldradiohistory.com/BOOKSH...13-OCR.pdf.

For some reason, many schematics of this era are published without pin numbers for the tubes. In addition, the RCA Receiving tube has some great descriptions of circuits that these tubes are designed for, and a good description of the "Pentagrid Convertor tube", introduced around 1933 or so.

I will post more later, when I get snowed in.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
Philco 39-7 issues - by Jeff Lepore - 02-19-2026, 12:02 PM
RE: Philco 39-7 issues - by morzh - 02-19-2026, 12:56 PM
RE: Philco 39-7 issues - by MrFixr55 - 02-19-2026, 04:06 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-19-2026, 07:05 PM
RE: Philco 39-7 issues - by Joe Rossi - 02-19-2026, 08:37 PM
RE: Philco 39-7 issues - by morzh - 02-19-2026, 09:35 PM
RE: Philco 39-7 issues - by MrFixr55 - 02-20-2026, 10:25 AM
RE: Philco 39-7 issues - by Jeff Lepore - 02-20-2026, 04:39 PM
RE: Philco 39-7 issues - by morzh - 02-20-2026, 04:49 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-20-2026, 05:53 PM
RE: Philco 39-7 issues - by morzh - 02-20-2026, 10:22 PM
RE: Philco 39-7 issues - by MrFixr55 - 02-21-2026, 09:46 AM
RE: Philco 39-7 issues - by Jeff Lepore - 02-21-2026, 11:21 AM
RE: Philco 39-7 issues - by RodB - 02-21-2026, 12:18 PM
RE: Philco 39-7 issues - by morzh - 02-21-2026, 12:37 PM
RE: Philco 39-7 issues - by MrFixr55 - 02-21-2026, 02:09 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-21-2026, 06:48 PM
RE: Philco 39-7 issues - by morzh - 02-21-2026, 07:13 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-21-2026, 09:25 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-21-2026, 09:51 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-21-2026, 10:57 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-22-2026, 10:22 AM
RE: Philco 39-7 issues - by MrFixr55 - 02-22-2026, 10:49 AM
RE: Philco 39-7 issues - by RodB - 02-22-2026, 11:28 AM
RE: Philco 39-7 issues - by morzh - 02-22-2026, 02:02 PM
RE: Philco 39-7 issues - by RodB - 02-22-2026, 02:49 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-22-2026, 07:03 PM
RE: Philco 39-7 issues - by morzh - 02-22-2026, 07:26 PM
RE: Philco 39-7 issues - by morzh - 02-22-2026, 07:31 PM
RE: Philco 39-7 issues - by RodB - 02-22-2026, 09:07 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-23-2026, 06:54 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-24-2026, 07:32 PM
RE: Philco 39-7 issues - by morzh - 02-24-2026, 08:35 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-25-2026, 12:44 PM
RE: Philco 39-7 issues - by morzh - 02-25-2026, 02:18 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-25-2026, 06:34 PM
RE: Philco 39-7 issues - by morzh - 02-25-2026, 09:08 PM
RE: Philco 39-7 issues - by MrFixr55 - 02-25-2026, 09:31 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-26-2026, 12:45 PM
RE: Philco 39-7 issues - by MrFixr55 - 02-26-2026, 03:02 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-26-2026, 03:24 PM
RE: Philco 39-7 issues - by morzh - 02-26-2026, 03:50 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-26-2026, 06:25 PM
RE: Philco 39-7 issues - by morzh - 02-26-2026, 09:50 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-26-2026, 10:36 PM
RE: Philco 39-7 issues - by morzh - 02-26-2026, 10:49 PM
RE: Philco 39-7 issues - by Jeff Lepore - 02-28-2026, 12:34 PM
RE: Philco 39-7 issues - by morzh - 02-28-2026, 02:21 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
hello david, I have a similar generator in my collection that features a cast iron, single-cylinder Briggs & Stratt...radiorich — 01:00 AM
under chassis parts locator diagram for 1938 Zenith 9s262
Has anyone gone to the trouble of creating an under chassis parts locator image?  Yes, I can identify components by foll...bobloney — 08:57 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Try looking at this site the book mark is for a old generator that I was given. David    https://radionerds.com/index.ph...David — 08:36 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Hello Everyone, I am looking for voltage identification for all the pin positions on the socket of a CRV-20130 power su...Tonym4704 — 08:16 PM
Philco P45-6365 Universal Transformer Instruction Manual
Can anyone guide me to where this may be found?GRG — 03:00 PM
54C Complete Teardown/Rebuild
I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM

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

>