[klondike98]

I believe this model was manufactured for a couple years after its introduction in 1946 based on the Telechron.net website. They say the price was in the $29.95 to $35.65 range. $29.95 in 1946 is about $497 in 2026 dollars.

Here's the SCHEMATIC LINK. I did notice that instead of the 35Z5GT rectifier tube specified in the schematic, there is a 35W4GT tube in the radio. Looks factory to me and had to be a modifcation at some point since the Z5 is an 8 pin tube; the W4 a 7 pin and the socket is a 7 pin socket.

   

   

As I mentioned in the "New Years Finds" thread, the Alarm/Radio ON/OFF stem is broken off and the two knobs that go with the clock are missing. After looking around I did find a possible stem fix that may or may not actually work (Renovated Radios has a stem repair kit) but for just a bit more than the price of that plus a couple of new knobs I was able to locate a working Telechron 8H61 alarm switch that I think will be a drop in solution. We'll see once it is here.

Its a bit dusty inside but I think it will clean up well. Under the chassis is pretty clean although its another tight fit for recapping.
   
   

The cabinet came up nicely after a clean and polish.
   

More later...

[klondike98]

The cardboard cover on the electrolytic can came off with just a little warming and a twist. A hacksaw followed by cleaning out the old capcitor remains at the base of the can and I think it will be easy to rebuild the electrolytics here. Its a 40, 30, and 20 uF multicap.
   
   

[morzh]

Bob

Did the cardboard cover a regular twistlock under it?

[klondike98]

Yes it did, now that I think about it, I wonder why they put the cardboard on it. I better take a closer look at the can and markings on it and trace the wiring. B- is isolated from the chassis ground by C2 but from the pictures I've take it sure looks like one end of R6 1meg ohm is soldered to the twist lock while the schematic shows it should be on B+ and the Plate of 12SQ7. It always take me awhile to sort out the schematic and I haven't spent enough time with it yet. I did photo the markings on the can for reference.
   
   

[morzh]

I had that once. Both the twistlock inside and the cardboard had the capacitances etc marked on them.
Forgot what radio that was.

[radiorich]

Hello bob,
It is looking great so far !!
Sincerely Richard

[MrFixr55]

Likely the cardboard cover over the twistlock and the twistlock floating from the chassis to meet UL requirements for shock protection if there was no interlock on the back. Apparently, they started to think a little about safety in postwar radios. Later sets had the all-paper "firecracker" jobs which did not hold up the way that the metal ones did.

It was not uncommon to see these "hybrid" octal / miniature combinations, as some manufacturers, especially the smaller ones, but even RCA, switching mid run from octal to miniature tubes as the octals ran out, with such weird combos such as the output and rectifier being 7 pin minis (50B5 / 50C5, 35W4), but the other tubes being octal and possibly metal. The chassis was punched for octals and either an adaptor existed or, more commonly, a phenolic 7 pin socket with dimensions to fill the hole for an octal socket was used. I remember seeing a set (possibly an RCA) on eBay, having all 7 pin AA5 tubes except the IF which was a metal 12SK7, possibly because they tried an unshielded 12BA6 and it didn't work, and they did not want to spring for a shield and a way to ground it or to redesign the chassis layout to deal with it.

A pipe cutter makes a clean job of cutting the cap fgor restuffing.

[klondike98]

I need to spend more time reading the schematic info before I start posting! It says right on it that later sets used the 35W4 with slightly modified wiring. I also need my colorblind glasses. That 1meg resistor I thought I saw in the photo is really 10meg and exactly where it’s supposed to be. Brown-Black-BLUE, not green! Tubes are on order along with an an electrolytic I need.

[Arran]

I think that the combination of tubes with different bases had a lot to do with whatever the manufacturer could get in quantity, or get cheaply. I have a few Philco sets from 1950, the U.S version was called a 50-524, in Canada they labeled it as a model 84 for some strange reason, and those sets used three different series of AC/DC tubes, loctals, octals, and seven pin miniatures. I think that there may have been a valid engineering reason to use the larger tubes for the rectifier, and power output, if only for heat dissipation, but they could have skipped using loctals in the rest of the chassis, other then the fact Philco probably had a warehouse full of them.
There was one line of sets made by one manufacturer that strangely never switched to seven pin tubes at all, and that was Arvin in their metal sets. You would think that in such a tiny radio that they would have come up with a new circuit, using the seven pin tubes, maybe even made them a proper AA5, but Arvin never did, they used the same four tube setup from 1946 right until they quit making them, in 1956 I think.
Anyhow the Telechron (G.E) radio is a TRF of some description, I guess they figured that these would mostly be of interest to city folk, and nobody would be band scanning for DX. Without finding some engineering memos we may never know.
Regards
Arran

[klondike98]

Just to all be on the same page, the corrected or updated schematic is seen below:

   

There are 3 electrolytics and 6 paper caps in the radio to be replaced. C14 will get replaced with a Y2X1 safety cap. All the resistors seem to be within spec. Because of the small chassis and tight fit, I'll probably remove all the paper caps at the same time to be able to have better access to reinstall them.

[radiorich]

Hello Bob,
So if that resistor came out and bit you then maybe you could see it was a 10 meg.
today at work I was designing a simple flasher circuit to show the students how to use Tinkercad and I put cap in backwards and it went bang !!

Sincerely Richard

[klondike98]

LOL Richard! I can't say that's the first time I've misread something, nor will it be the last. My other mistake is usually miscounting the tube pin numbers and soldering a component to the wrong pin. I did that on a Zenith Transoceanic once and it took me forever to find my mistake.

[Arran]

Bob;
I hope your mistake was not in the front end of that T.O, those are not easy to get into? The tube pins are always numbered clockwise from the underside of the chassis, anticlockwise from the top, I have a Phonola where someone made that mistake at the factory on a 6K7 IF amplifier tube. Imagine this, the radio left the factory in 1936 or 37, and nobody caught the mistake until I was checking the set over in 2023, and it was not untouched, it had hit the service shop a few times for tube replacements, filter caps, and a few paper caps over the years.
What I was doing was trying to trace out the wiring to a bypass condenser block, so as I was following the schematic I noticed that the cathode and suppressor grid were supposed to be tied together, the cathode was above B- because it had a cathode resistor/capacitor combo, but the suppressor grid was tied to chassis. So I looked through the catalogue of other Phonola sets from the same year, and all the others, including my 32 volt one, were wired with the two elements tied together. I'm guessing that the set must have played that way, but what that did to the life of that tube I'm not sure, it was a replacement tube and IF amplifier tubes are usually long lived.
Regards
Arran

[RodB]

A couple years ago my son brought me a guitar amp to fix that a local artist owned. He bought it from someone and wanted to use it for practice. When I got to the chassis and powered it up, just a mild hum from the speaker. So, I went to feed a signal to the grid of the output tube and the tube pin was bare, no wire, no solder, shiny clean. Found the coupling cap from the previous tube connected to the pin next to the grid pin of the output tube. This is a beat up no name guitar amp from the 70s that never worked. Recapped it and it has a new life. Happy Camper by Wiĺlie Nelson.

[morzh]

About 48 years ago I was improving some military educational thing and needed to use a cap. I used a 30uF electrolytic (300V or so, Soviet) but forgot that it would see an AC signal.
It went kaboom...after a while. But the smell....and the unrolled isolation paper from inside...and confetti...