[TV MAN]

So far, so good. 70 ohm cathode bias resistor. Now, I can start going back together with this thing. The RF side of the volume control is pretty bad, but the 250 ohm side seems decent. I have heard there is a resistor bypass that is used eliminate this. Does anyone know how this is done?

[TV MAN]

I believe I have the intermittent solved! It was the 70 ohm section of the large voltage divider/bias resistor. I replaced that section with a 2w carbon resistor and have a good volume control installed. It has been proving itself good for the last two weeks.

My radio on "Life Support"
   

Volume control repair and replacement for 70 ohm resistor:
   

Underside shot of completed chassis:
   

It's sitting on my bench playing after touching up the alignment:
   


This was a very difficult problem to solve, and tested about every skill and piece of test equipment I own! One thing I noted about this fault, it didnt have the usual sharp static of a bad connection, it had more of a "thumping" type sound which could be best heard with no modulation on the generator.

In the end, a Simpson 260 on the microamp setting in series with a pot so I wouldnt trip the breaker, lead me to the problem. Voltage tests were useless. Resistance tests also showed correctly. When I unsoldered the leads on the big resistor, I found 3 clipped off pieces of wire in the solder, so I would say I wasnt the only one trying to track this problem down, and is probably what put the radio in the attic. I'll play it for a couple of weeks to make sure no other problems show up, and check back in with the results.

[TV MAN]

I now pronounce this "Project complete"!

This was my first full restoration of any radio, and the 1st I have worked on that was this old. This would have been much more difficult (maybe impossible) without the help and support of the members of this web site and information in here. With the internet, parts availability has become easier as well as info.

Here are a few tips on this experiance:
1. Tube shield - PUT IT ON when testing this radio!
2. Open RF coil - had to rewind
3. Bad RF tube - checked perfect on tester, would start strong but lose emission after a few minutes under load, lowering volume
4. Volume control, I had to replace this, found used but good part, cleaned up with Deoxit
5. Big voltage divider resistor, bad 70 ohm to ground section. This was intermittent. Took months to find this one!
6. Repaired scratchy speaker by removing cone and cleaning.
7. When aligning, follow the instructions exactally!
8. Yes, full recap of all exc micas
9. Full set of NOS tubes
10. I lubed up the shaft on the tuner where it sits in the housing. This helped the slipping tuning shaft problem since the rotor turns easier.

A few comments:

Blessed are the ones that can simply recap a radio and have it work perfectly. Many were put up because of other problems, and this can be simple to major to repair. I feel for anyone who ends up with an intermittent or something difficult to find, esp if this is your first restoration, even more if your inexperianced with little to no test equipment. However, with the help of those in this web site, you can do it!

Here are a couple shots of the finished project:
   
   

Thanks For all the help and advice with this project!

[OldRestorer]

[morzh]

Hey Tim,

Praise the Philco Gods!
Congrats!

[gregb]

Isnt this the greatest feeling ever to give one of these old radios a new life! Can you just imagine what has been heard through the speaker of this radio over all its years of operation and just imagine what will be heard through it for years to come.
Enjoy it and listen to it every chance you get.

Gregb

[TV MAN]

Here is a RARE picture in this day and age! This shot was NOT staged! This is my 7 year old boy listening to Bible storys on our local Christian radio station on our newly restored 70.


   

[morzh]

Great picture.

[Eliot Ness]

Great picture

+1