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Philco Model 20 distortion
#2

(04-15-2012, 10:34 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, 10:34 PM
RE: Philco Model 20 distortion - by 7estatdef - 04-16-2012, 08:17 AM
RE: Philco Model 20 distortion - by morzh - 04-16-2012, 12:42 PM
RE: Philco Model 20 distortion - by Chuck Schwark - 04-16-2012, 01:18 PM
RE: Philco Model 20 distortion - by morzh - 04-16-2012, 03:19 PM
RE: Philco Model 20 distortion - by 93foxconvert - 05-06-2012, 12:21 PM



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