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

Thread Closed

Philco Model 20 distortion
#2

(04-15-2012, 11:34 PM)93foxconvert Wrote:  Hi all. This is my first post on the phorum. I have been restoring radios for about 2 years and this was my first Philco. I wouldn't have gotten as far as I did without the help of the phorum.

I was given this Philco 20 as the owner did not want to spend money getting it restored. Otherwise, at this stage of my experience, I likely wouldn't have tackled this little gem.

The 20's sound is distorted. Using my signal tracer, I can hear the distorted sound at the detector.

Here's what I've done:
replaced all the tubes (most tested bad), replaced all caps (including those in the large can) and resistors, cleaned all the tube pins and tube sockets. All the while learning new things like Philco bakelite caps and such. I double checked my wiring.

The radio is very sensitive with just a 10 foot wire antenna but even at low volumes, the sound is distorted.

When I began on the radio, someone had left the large cap can wired into the radio but added 1 20uf electrolytic. It hummed and didn't receive any signal. As I progressed replacing caps and resistors, I got it to receive. The 27 tube tested very poor and when I replaced that, it really came to life, albeit with a hum and distortion.

After finishing with all caps and tubes, the hum is virtually gone but I'm left with distortion/garbled sound.

What is my next step?

Hi & Welcome!!
Check the HV to see if it is too high. If that 20mf cap is tied to the filament of the 80 your HV will be significantly higher. Replace filters with the same mf rating as originals on this set.
Best I remember there is a mica cap on the plate of the 27 may want to replace it too.
Keep us posted
Terry
ps Does it have it's tube shield??


Messages In This Thread
Philco Model 20 distortion - by 93foxconvert - 04-15-2012, 11:34 PM
RE: Philco Model 20 distortion - by 7estatdef - 04-16-2012, 09:17 AM
RE: Philco Model 20 distortion - by morzh - 04-16-2012, 01:42 PM
RE: Philco Model 20 distortion - by Chuck Schwark - 04-16-2012, 02:18 PM
RE: Philco Model 20 distortion - by morzh - 04-16-2012, 04:19 PM
RE: Philco Model 20 distortion - by 93foxconvert - 05-06-2012, 01:21 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
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
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM

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

>