[rfeenstra]

It's amazing how the colors have changed over the years!

[Greg]

Finally back to it.

I managed to polish up the chassis so that it looks pretty decent. After that I figured I needed to give the capacitor can (part 89) a fresh coat of tin. So I did a chemistry experiment. I think it turned out OK. The tube shields may be next, after the rest is done.

   

Which is the "red" and which is the "brown" wire in the photo below? Like a dummy I snipped the wires without taking a picture or noting which came from which cap when I disassembled them. They're marked as I connected them. I know I'll connect them correctly, but for some reason I'd like the colors to be right. I think the one I'm calling brown (bottom one) is really red, or was red 80 years ago...

There's a back that will be glued on to keep them from shorting in the can.

   


I still need to fix (rewind) the phase splitter transformer (32-7057). If I'm luck, very lucky, I'll find one at Kutztown before I start.

I also have a bad power supply choke but found a replacement on Ebay. Strangely, different part number, but the exact same specs according to the catalog, resistance, inductance and size.

[Greg]

Well I powered it up for the first time. It "worked" = no smoke/fire and some stations on BC and SW bands. One small thing is that I had the center tap of the power transformer connected to only one of the two first stage 8uF filter caps, so no B+. I fixed it, but for some reason the negative terminals of those caps were connected to each other, but indirectly - not a wire between them. I was wrong...

I'm pretty all of the alignment adjustments are shot since I cleaned the rust from all of the trimmers and there are A LOT of trimmers.

I did make new bases for the 8uF filter caps. The ones installed were replacements with wires, not the stud thing the original ones had. They look pretty OK, but the paint is too "glittery". However it does stick to the urethane.

   

I did replace all of the out of tolerance resistors and restuff all of the paper and Bakelite capacitors. I also replaced "crunchy" wires.

    part

Kind of looks like it did when I started. I guess that's a good thing. It's too bad the wire color fades so badly with age.  I left the tags I used to mark the wires on them. That way I have a little to work with if a bug turns up. It's hard to see, but there is a safety pin used to snug the IF tuning shaft. I need to remember to replace it with a c ring or whatever they're called. The pin's kind of tacky - no pun intended.

Tomorrow I'll probably start alignment. I'll see if that turns up any more bugs.

Someday I need to repair the light sockets. The rubber or whatever it was bases have disintegrated in several of them.

[rfeenstra]

Keep up the good work. These are great radios! I have 2 plus a 38-116.

[morzh]

Scond Rob's note.

Clean chassis, nice.

They are some of the best sounding sets out there. Along with the 690, both years 37 and 38.

[Radioroslyn]

+1 to Rob's comments too!

Very nice clean job! I to have two of the 37-116's also  a 121 & a 122. Just need to get off of my rumpus and dive in.

[KCMike]

Very good job Greg.

[Greg]

Hi - I have a question about reassembling my automatic tuning mechanism.

How do I set the tuning capacitor and align the "big round thing that has the presets and that holds the dial"?

Do I fully close or open the tuning capacitor and set "A" against the  stop "B"? See photo.

From my disassembly photos it looks like the "square box" embossed on the front of the "big round thing" aligns with midway on the dial. See second photo. I suppose I should probably be able to figure it out form there.

Thanks...

   






   

[Greg]

Two issues now. I think figured out the last problem

1) The band "mask" is getting "pinched" so that it wants to turn with the dial. I'm 99.9% sure it's all installed correctly. The "reflector" 1st, the mask 2nd, the "retaining ring" 3rd, the dial 4th and the "ring that holds the station tabs" 5th.

When I screw down the "ring that hold the station tabs" it compresses the lot and causes the mask to get pinched. If I release the screws a bit it works. Beats me what's going on or how to fix.

2) No reception on the 2nd SW band ~4.5-7.5 MHz. Ugh... I checked ALL of the coils when I started. I thought it worked earlier, but maybe not. The oscillator seems to be working. I set my portable SW radio to ~6 MHz and I hear the "pop" as I tune past 6MHz on the 37-116. Time to start working my way through it. That's for tomorrow...

Greg

[rfeenstra]

It seems to me that I remember that the ID of the mask had shrunk on one of mine. I had to gently, with sand paper, increase the ID to allow it to not grip the drum.

It is very common on these for the osc. coil on band 2 to have the Philco nitro cellulose disease. I had to rewind both osc. coils on my 37-116's. If you see green on the coil, rewind it! Most here who have worked on these have had problems with band 2 because of the coil. I know on one of mine, the coil originally measured ok, but by the time I got it reassembled, it was bad.

[Greg]

Update....

I'm still a bit incredulous, but the SW band is now working. I knew the oscillator was working, so I connected my signal generator to the grid cap of the mixer tube. Maybe the RF coil was bad. I could hear the generator as expected. But I noticed that when I jostled the connector it seemed to receive. The connection with the cap was very loose. I crushed the connector a bit to tighten it. It was fine after that. Why it worked on the other bands, I don't know. The only thing I can think of is that all were not performing well and that band's alignment is the worst and that was enough to kill it.


The dial assembly is still a problem.

Putting things back together I first slipped "A" the reflector over the drum. Next the mask, "B". Next the spacer ring, "C". Next the dial, "D". Next the thing that holds the station tabs and holds the whole lot together, "E". Can't see it here.

The problem is when I tighten the screws on "E", it presses the dial against the spacer (OK), pressing the spacer against the mask (not OK) and the mask against the reflector and the reflector against the "flange" (can't see it) on the drum.

Since the mask doesn't on the spacer, it gets compressed and would like to turn with the dial. Did I put  this together incorrectly? It sure doesn't look like that when I look at my disassembly photos.

   

[rfeenstra]

It has been a while since I worked on mine but I'm thinking that the shadow mask should ride loosely on the spacer, not get pinched between the spacer and the reflector.  Is I said, mine had shrunk and I needed to sand out the inside diameter to get it to float on the ring.  somewhere there is a Philco drawing of the assembly of the auto tune system but I can't find it now.

I found it in my files but I can't post it here. the file is too large. It is Philco service bulletin No. 273 - Auto Tune. Acording to the drawing in buletin, I was wrong about the shadow mask riding on the ring. Instead the ring is supposed to stop before it pinches the shadow mask and the reflector.


OK. I found it: https://philcoradio.com/library/index.ph...bulletins/

[Greg]

AFC (Magnetic Tuning) Won't work and I'm a bit confused. What/were (physically) is switch part #135?...

I'm almost done, except the magnetic tuning doesn't work. The IF alignment seemed to go well, things peaked, etc.. The tube voltages look sane. My suspicion is centered around the switch, part #93.
- When OFF points "A" and "B" measure grounded - GOOD.
- When ON  points "A" and "B" have a ~2ohm resistance between them - BAD - I think.

But, before I go and fool with the Magnetic Tuning switch (93), I need to figure out what the switch below it, part 135 (or so it says) is supposed to be.

Switch 135 seems to be able to connect points "A" and "B". So, maybe why I see the ~2 ohms (seems a bit high)?

What doesn't make sense is that Ride's lists part 135 as "Pilot Lamp (Codes 121-122). I don't think so.

The text below the arrow at the bottom of the schematic says "USED IN CODE 122 ONLY" (chopped it off).
   

[Phlogiston]

YES, it is very often intermittent. The switch is actually 2 on/off switches in one (as I recall). The ones I have worked on have always been a problem.

[Phlogiston]

Oh, yes, it also switches on/off the push-button dial lights. Phone dial lights on = Mag tuning on.