Philco 39-30 restoration

[bandersen]

Here's another long neglected project that I'm finally finishing

It's a slant Philco 39-30 table top. It covers the BC and 5.0 - 18 MHz bands and features 8 presets.
The original finish is in pretty good condition but the decals around the controls are pretty bad. I picked up a set of repros and will attempt to carefully sand them off and apply the new ones. Then clear coat the whole set with some lacquer.



The three electrolytics and one power resistor were replaced ages ago, but the rest looks original.


I also picked up a set or repro push buttons and plastic dial face.


The yellow caps are from when I started recapping this set a few years ago.

[bandersen]

First, I'm tackling the brittle power transformer insulation.


I spliced in new wires that match the colors indicated on the schematic. Then, I sealed it with some hi grade wax.

[Reece]

I always liked those sets. A neighbor had one when I was real little and he'd sit and listen to baseball in the evenings on it. Is that photofinish?

[bandersen]

Originally Posted by Reece

I always liked those sets. A neighbor had one when I was real little and he'd sit and listen to baseball in the evenings on it. Is that photofinish?

Nope, it's real veneer

Here it is after cleaning with GoJo and a Howard's RAF wipe down.

[bandersen]

I found the primary on the output transformer was open and had to perform some surgery. I hope it holds up.


Then more surgery on an IF transformer. The hard rubber wire insulation is falling off, the resistor is out of spec. and the mounting screw has broken loose.

[JohnHacker1]

Looking good!

[wa2ise]

There was and maybe still is a guy on the old usenews group rec.antique.radio+phono Bill Turner who could make replicas of the radio dial cover. You send him an outline of the dial opening, and he would cut a jig out of masonite and heat form a new cover. But it's been a while since I hung out on that forum.

[bandersen]

I read about that technique and gave it a try a while back.




It worked OK, but I had trouble getting it just right and eventually, I picked one up from this guy.
It's a good fit, but I have not installed it yet. He included little brass rivets to hold it in place.

[bandersen]

I finally finished the recap and fired it up for the first time.
Once the radio is working, I'll mount those electrolytic caps more securely.

At first it was howling with feedback then I realized I forgot to reinstall the 75 tube shield.

It's working fairly well on both AM and SW, but not as much gain as I expected. Next, I'll double check all the voltages and do an alignment.

[bandersen]

I couldn't get the presets to work properly and eventually found this bad 370 pF mica cap (#10 on the schematic).
It works with the adjustable coils to set the LO oscillator frequency.



Each preset slug only covers a portion of the BC band as shown on the chassis.


Replacing it with a 390pF got the presets working, but I couldn't tune below 800 kHz on the first four presets. I bumped it up to 500 pF which go me down to 680 kHz.

I suppose I could increase the capacitance even more, but I'd like to know why the tuning range is so far off

[Reece]

Preset coils: I was thinking maybe the coils had absorbed moisture but that makes me think they'd go lower? Anyway, I'd try training a desk lamp on the coils for a couple of days to warm them.

[bandersen]

Interesting suggestion. I bumped the capacitance up on cap #11 by 100pF and that got me right down to 550 kHz.
I'm curious now to try drying out the coils as suggested and see if the presets drift any.

Meanwhile, I'm moving on the the cabinet. The only really issue it has is crummy decals.
I'm very carefully sanding off the old ones, then I'll give the whole cabinet a light 320 grit sanding. Next, a little Howard's walnut ARF to refresh the color a bit.
Then apply the repro. decals and, finally, give it a few coats of fresh lacquer.

[bandersen]

The grille cloth and backer was stapled to the inside of the cabinet. Some pliers took care of that.


The cloth is dirty, but intact. I've heard that K2r spot lifter works well. http://www.k2rbrands.com/products/original.htm I'll try to track some down and give it a try.

[CoogarXR]

I love reading restoration threads. I don't really have anything worthwhile to say, other than "rah-rah!" you (and everybody else who makes threads like this) are my heroes

[bandersen]

Thanks! I've had the radio playing for a while and it's starting to act up. Stations fade and static increases after it's been playing 5+ minutes. I'll go through and recheck voltages etc. Maybe one of the old mica caps is acting up ?

Meanwhile, I'm making progress on the cabinet. I filled in all the cracks and chips with lacquer sanding sealer until it was nice and smooth.
One decal has been applied with four more to go.


I also picked up some K2r and gave it a try. It's cleaner, not like new, but cleaner for sure.