Philco 39-30 restoration
 

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.

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The three electrolytics and one power resistor were replaced ages ago, but the rest looks original.
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I also picked up a set or repro push buttons and plastic dial face.
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The yellow caps are from when I started recapping this set a few years ago.
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First, I'm tackling the brittle power transformer insulation.
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I spliced in new wires that match the colors indicated on the schematic. Then, I sealed it with some hi grade wax.
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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.
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I found the primary on the output transformer was open and had to perform some surgery. I hope it holds up.
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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.
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Looking good!

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

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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.

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.
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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.

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.

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Each preset slug only covers a portion of the BC band as shown on the chassis.
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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 :scratch2:
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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.

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

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.
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I also picked up some K2r and gave it a try. It's cleaner, not like new, but cleaner for sure.
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With the help of a guideline, I finished applying all the decals. Not my favorite task at all :no:
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looks really nice. are those decals the kind you soak in water? If so won't the water hurt the finish?

Yes, they're water-slide decals. Only a small amount of water is needed to slide them off their backer. I blot most of the excess off with a soft paper napkin and the remainder dries quickly.

I tell you what, you've done a lot of work to this set and its beautifull. I am really glad that people like yourself post step by step work and problems to so we learn diagnosis and quality repair. In my town I only know one person who knows repair but they are too busy for me to rely on. Every question I ask and every thread I read is electronics school to be honest. Keep em coming!

The radio came with replacement electrolytics. I found the original part #s, did a web search and, amazingly, found someone selling a couple :)

Check out the bulge in the one on the right. I wonder if it was made that way or did that much pressure build up inside ?

I'm going to be cutting them open just below the lip on top and restuffing them.
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I also sprayed on the first coat of gloss lacquer.
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Looking really good!

Thanks! I'm still fighting with one issue. There's a really loud buzzing all through the broadcast band. It mostly fades away when a strong station is tuned in. SW band is fine. All the specified tube voltages match the service info.

I've replaced every paper and mica cap except for the triple stacked one inside the 2nd IF can. It's a sandwich of 100pF, 100pF and a variable made from exposed sheets of mica. I hope I don't have to mess with it.

Perhaps it's feedback or an AVC issue ?

Philco 39-30 Questions
 

Good morning. Great pictorial journal. It has helped me with the 39-30 I am working on.

I am nearly done with the electronics, but I have a couple of questions:
Does yours have a separate antenna, or just use a longwire off the Antenna screw on the back? I have located a guy selling repro laser-cut backs for this model, but neither mine nor another I've seen photos of have mounting holes for a back.

Do you have a source for the longer push-buttons for this model?

I pick up the power transformer I located tomorrow, and look forward to aligning it and hearing it play. I had to replace all the rubber-coated wiring, even inside the IF cans. But it was a great learning laboratory for me.

Thanks for taking the time to document the restoration. The couple of pictorial journals and YouTube clips on 39-30 restoration helped me a lot. I was nearly finished with mine before I discovered those, but I'll do a pictorial journal of my future restorations.

Regards,
Clarence
[email protected]

Where did you find the repro decals?

Clarence: this set is designed for a long wire antenna, can't take a loop. Bob: the buzzing--could be local interference, fluorescent light, etc. etc. Try the radio at another location. Try a ground. All that noisy junk wasn't around in 1939.

Greetings, I did find a link for the longer style push buttons the 1939s used, including many of the 39-30 models:
http://www.renovatedradios.com/parts.html#pushbuttons

The down side is they are $34.00, but that's for a set of eight.

Thanks. I'm having to dig a little since I starting working on this set a few years ago.

I got the decals from Radio Daze. Controls are set #DCL-39-25. The logo decal came from set #DCL-PH-HiFi. Just trim off the "High Fidelity" part. The font and spacing on the other logo decals is just not right.

I'm pretty sure I got the pushbuttons from Antique Radio Knobs: http://www.antiqueradioknobs.com/partlistings.html

There was no back on this radio. I don't think any 1930s Philco table top radios had backs for that matter.

I'm pretty sure you're right. I was hoping it was just this radio, but I'm getting interference to varying degrees on all my radios now :(

Grounding the chassis did the trick :banana: The noise isn't completely gone, but it's significantly reduced.

Yay! Do you have "safety" caps where the line comes in? Sometimes one from each side of the line to chassis helps, and even on top of that some will put another across the line. These are always connected so that they are after the switch.

Yes, 0.015 uF X2 safety caps from each side to the chassis. One is after the switch. The other one is always in circuit.

Oh yes, I'm very happy that it's working. So many other things could have gone wrong like the hacked up power and output transformers.

I took a whack at retuffing the can caps tonight. I was surprised at how easy it was to cut them open with just a sharp utility knife and gently rolling action. Even more surprised at how much liquid came out. I'm glad I had some napkins handy!
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I soldered on some extension wires and threaded them through the hole at the bottom. Then popped the tops back up, mounted and wired them in.

That just leaves one non Philco cap. Anyone have a spare 30-2330 (8mfd, 400v) ? Or anything close that would fit.
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My power transformer was bad, and I had trouble finding a replacement by the Philco part number. But I determined the specs and found a cross-match in one a fellow radio club member gave me. I verified the specs through testing the transformer's resistance and voltage readings:

It is an RCA part with number 970445-1 printed on the case.
It matched the voltages of the Philco 32-7976 at 250-0-250 and 6.3v, and
even the bolt holes lined up without chassis modification.
Perhaps someone else wanting a transformer for a Philco 39-30 will find
this cross-match useful.

Thanks for the info.
It's pushing 80 in my attic so I'm able to spray in mid March. Crazy!
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I'm finally just about done with this set!
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I painted the edges around the speaker by hand with dark paint.
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The radio came with these long "U" shims under the chassis. I wonder if they are factory or were they a later addition to compensate for mushed down rubber corner mounts ?
I've replaced the old mounts with reproductions and the shims seem redundant now.

Has anyone encountered these before ?
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This has turned out really sharp. Excellent hand work around those speaker grille openings.

Never seen those shims on a Philco before, but it's curious how they happen to be almost perfect in length for that chassis.

As usual, an excellent restoration job. Those shims are probably shipping shims that no one bothered to remove.

It looks to me like they're about 1/2" too short for the full length of the chassis, and about 1/2 - 3/4" too long to fit between the rubber pads.

This is just a guess, but I'd say they were factory equipment, just on a different radio. Just judging by similar systems I've seen in the past, I'd suspect their original purpose was to work as a guide for reinstalling a chassis... they were probably secured to the interior bottom of the cabinet in some way, maybe in a recessed channel, and the matching chassis would have had some sort of nuts or bushings along the bottom edge that would have slid in between the forks and provided a quick and easy way to line up the screw holes.

I spent a couple days rubbing out the cabinet and boy are my arms tired!
I hope to finish off this project later tonight :)
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Another one showroom fresh, Bob!

Thanks!. I think it's my best cabinet restoration so far. Soon I may feel up to finally tackling my 15DX :)
At long last, it's a wrap :D The only thing left is to print out some station preset inserts.

In retrospect I'm kind of amazed it's working at all considering the rotted wiring, open output transformer etc...

BTW I left the U channel shims out and the chassis lines up fine.

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