[Ron Ramirez]

I can't reinstall the RF unit just yet.

The ball bearing tuning shaft assembly is badly gummed up and can barely be turned.

So, I removed the shaft assembly...

[Image: http://www.philcoradio.com/images/phorum/37640_072.jpg]

There is a "C" clip in back which holds this unit together. I removed the clip with the help of two small flat-blade screwdrivers...

[Image: http://www.philcoradio.com/images/phorum/37640_073.jpg]

...and with some difficulty, I managed to get the parts taken apart.

[Image: http://www.philcoradio.com/images/phorum/37640_074.jpg]

All of these parts are caked up with dried out grease. I am going to have to soak these parts in a suitable degreaser. Afterwards, I will need to clean the parts thoroughly, add white lithium grease, and reassemble.

[morzh]

No wonder....

[Ron Ramirez]

So...after soaking the parts in ammonia for over an hour, I removed everything, rinsed the parts in hot water, and let them air dry. Then I returned them to the bench, and finished cleaning the pieces with denatured alcohol.

I could have just soaked the parts in denatured alcohol, I suppose...

...but anyway, the parts were now clean:

[Image: http://www.philcoradio.com/images/phorum/37640_075.jpg]

Reassembly was the reverse of disassembly. Only, I had to add a liberal amount of white lithium grease before reassembly.

The finished product:

[Image: http://www.philcoradio.com/images/phorum/37640_076.jpg]

[Image: http://www.philcoradio.com/images/phorum/37640_077.jpg]

Not only better looking, but much smoother now, and both inner and outer shafts easily rotate the tuning condenser without the knobs in place.

Interesting how the tuning condenser was rubber stamped 37-620. Well, the 37-640 uses the same RF unit as the 37-620 and 37-630.

[morzh]

Mineral spirits work for me. Also smells better than ammonia
I am not sure alcohol is a good solvent for any grease so using ammonia first was probably a good idea.

[Ron Ramirez]

Well...

after my last post, I got on a roll...and just kept working, without stopping to take pictures, until I was at a point where I could try it out.

[Image: http://www.philcoradio.com/images/phorum/37640_081.jpg]

It's Alive!

It was lots of fun getting to this point. NOT. After reinstalling the tuning shaft, I attempted to reinstall the RF unit into the main chassis. Then I could not get the band switch shaft to go completely back into the RF unit. I ended up removing the RF unit again, installing the band switch shaft, installing the RF unit, attaching its lone bolt, and then soldering its 12 leads (almost all of which I had made too long, and had to cut and restrip) to their respective points inside the main chassis.

I damaged one wire in the main chassis while reinstalling the RF unit, and had to replace it.

I had to connect a new wire from under the chassis to the 6Q7G grid cap.

I also had to find a set of tubes for it. The 6A8G and the two 6F6G tubes that came with it were OK, so they went back in. Most of the other sockets had small metal and ST tubes. I left those out, and populated the other sockets with ST (taper-top) tubes save for the rectifier socket. Here, I used a 5Y4GA instead of a taper-top 5Y4G. Why? Simple - since this chassis is going to be in a small, short cabinet, a 5Y4G would be very close to the underside of the top of the cabinet. Not a good thing as far as heat is concerned. The 5Y4GA is shorter and will allow for some clearance between cabinet top and the top of the rectifier tube.

Yes, I know, I could install some silicon diodes in an octal socket, but I would rather use a tube in this application.

I have not yet reinstalled the volume control shaft as you can see above. I left it out just in case I needed to remove the RF unit again for some reason.

I have not tried it on the two shortwave bands yet, but it seems to be fine on the lower end of AM, anyway. I'll give it a more comprehensive test tomorrow. Once I am sure it is OK, I will reinstall the volume control shaft, install all of the dial parts, and give it a good alignment.

Christmas is next weekend, so I am going to consider this my annual Christmas radio restoration.

[klondike98]

[Ron Ramirez]

Finally!

[Image: http://www.philcoradio.com/images/phorum/37640_082.jpg]

Last night before bedtime, I went back to the bench just long enough to see if the chassis was receiving on all three bands. It was - but boy, was that band switch ever dirty! And I hit the wafer sections with DeoxIT while I had the RF unit apart. Strange.

So...

Today, I sprayed the switch wafers again - this time, with contact cleaner - then I had to go out for awhile.

By the time I returned this evening, I felt the contact cleaner had had plenty of time to evaporate, so I tried it again and it was just fine.

I reinstalled the volume control shaft, gave the chassis a complete alignment, and now it has been moved into its new home - the 38-624T cabinet I refinished a couple months ago.

So...how well does a 37-640 chassis fit inside this cabinet?

[Image: http://www.philcoradio.com/images/phorum/37640_083.jpg]

Not too bad. The 5Y4GA has a fair amount of space between it and the top of the cabinet. I won't ever be playing this radio for hours on end anyway, so it should be fine.

I did have some trouble with clamping the shadowmeter in place. The clips and the frame behind the dial scale were interfering with one another. But I finally managed to get the shadowmeter clipped into place.

Yes, the shadow is off center. I'll address that issue later.

So that is it for this 37-640 chassis restoration. I've fallen way behind on answering emails, and I also have a number of thank-you notes to send out. My apologies. I just really wanted to get this finished. I'll spend the next 2-3 days catching up on things...so if you've sent me an email or if I owe you a thank-you note, be assured I am not ignoring you.

Now stay tuned for the next project - installing new power supply electrolytic capacitors (and new silicon rectifier diodes) in a Sherwood S-7900A receiver.

[KCMike]

  Great job Ron.

[Kenneth F. Besso Jr.]

WELL,it all fit very nicely . Maybe you can ,,,make a little piece of sheet metal …off ,,,of the back of the dial bracket ,,,for a hood,, to disperse the heat off the wood,,,from the tube,,,just a ideal,,,,other wise Beautiful---Cheers

[TV MAN]

Well done and very well documented! I think this thread would be a keeper and would fit nicely in the "Notebook" for future restorations of this model/type of chassis. Thanks Ron!

[bmheise]

Thank you for offering your wiring sketch in addition to suggesting that we draw one up.  Yours saved me a great deal of time and I'm glad I didn't make my own drawing first.
My 37-640 chassis had earlier repair that introduced a wiring fault. From your drawing, Red wire #9 terminates on pin 7 of the 6K7G socket and it of course comes from pin 2 of the 6A8G. 
I found my red wire, (if you can call it that after 83 years) tied to the ground near pin 8, effectively cutting the chassis heater daisy chain circuit. 
I can imagine the repair persons reaction when the radio went from whatever-the-problem to nothing except the dial lamp after they were done.
You sure saved a pretty fair amount of hair pulling on my part. Of that, I'm certain.

Thanks again!

[harley92]

Hi Ron,
I am doing a 37-620 which is about the same for the RF unit.
I have found an easier way to remove the RF chassis without removing the band switch shaft assembly.
After you remove the tuning dial mechanism as you have described and disconnected all wires going to the RF chassis, Just remove the eight 1/4 inch screws holding the front chassis plate and remove it with the volume control shaft attached (keeping track of the shaft clip on the volume control). Then remove the rear tuning chassis screw and rubber washers. The RF chassis will now tilt upward as you describe and slide forward without messing with the band switch shaft removal. This leaves a nice wide opening for filter rebuild and parts replacement.
Hope this helps.

[oldcoot]

Just got my 630 back together, and want to thank Ron and Harley92 for their excellent methods and suggestions. I found the chassis resto pretty grueling/stressful, most especially all the wire disconnecting and then re-hookup. But the methods worked, the fotos really helped, and together they made it possible for me, a novice hobbyist, to get this thing up and running. Thank you, gentlemen!