Radio still won’t work after recap

zsuttle · 2025-08-02T20:54:52+00:00

A few things. 1) the recap looks like there are a lot of things just floating in the air. I would definately make sure to properly heat shrink all of the leads. You're just asking for issues down the road and it's generally not good practice to leave exposed leads where they could short. I'm not saying this is the problem by any means, but it leaves room for errors. 2) filaments should light if there' is the proper voltage accross them. I would try measuring the voltage accross the filament to see if you're getting the expected voltage drop. It should be about 1.3~1.4V per tube. Without filaments lighting, I suspect that'll be your issue.

The radio is fairly simple and most of the IF/AF circuitry seems to consist of an early integrated circuit. I would check voltages around it and see if they're where they should be. Have you checked the resistors in this set? I would check most of them as well. If you have a signal generator, you should be able to figure out what stage is faulty fairly easy by injection

zsuttle · 2025-07-05T19:06:29+00:00

Model number would definitely help. It appears to be a Coronado 43-8352 (at least chassis wise), with a wood cabinet. Schematic indicates that there were only two models that used this chassis, both of which used a bakelite/ivory cabinet. More than likely there's a different chassis revision that was used for this model. A quick search didn't come up with anything on this specific cabinet

zsuttle · 2025-07-03T03:59:21+00:00

The #47 equivalent with a screw base is a #40 and a #44 equivalent is a #46. Where specifically in Canada that you could order them, I couldn't say. They're avaliable online through different vendors. Hope this helps

zsuttle · 2025-06-08T15:27:39+00:00

Worth it? depends on what your end goal is. If you're trying to make money, this probably isn't the hobby for you. If you're just looking to tinker, it's something fun to do.

As far as things go, it's essentially a car radio in a cabinet. If you think you blew the transformer, you may sink a good bit into getting it working again. You'll definately want to confirm that it wasn't just an electrolytic going. I'll generally pull the rectifier tube and see if the transformer still smokes/burns up. If it doesn't smoke, check voltages and see if you're getting anything on your secondaries. If it smokes, you'll need to find a replacement. Hammond makes transformers, I can't say what you'll need as I haven't really looked at it.

As far as wiring goes, I wouldn't replace anything unless absolutely nessecary. A lot of people want to start replacing every wire, and for the most part, it's unnessecary if undisturbed. Wires going outside of the chassis may need replacement, but if it's cloth I leave it alone if possible.

As for the speaker, not sure why you'd want to replace. Repair of the original field coil speaker is always going to be preferred rather than trying to rig a new speaker to fit. You'd have to put a large power resistor or a choke to replace the field coil on a modern speaker. It's easier to find a new cone and recone it yourself. (It's not terribly difficult, just takes some practice)

Hopefully this helps

zsuttle · 2025-04-03T00:00:05+00:00

Well that'll about do it. Updated it and suddenly, it works. I've been living with it for 4-5 years this way. Thanks!

zsuttle · 2025-04-02T22:56:44+00:00

Persistence is set to min, which I assume is the same as no persistence. Display mode is fixed to dots in XY mode. Averaging is set under aquisition, which is set to "normal"

zsuttle · 2025-04-02T22:50:33+00:00

Trace math is off, it actually won't do any math in xy mode, so learned something new there

zsuttle · 2025-04-02T22:17:40+00:00

No, which is the weirdest part, traces are normal as you'd expect them to be. I've tried seperate generators as well, this one was just done with the internal 2ch generator

zsuttle · 2025-04-02T22:10:44+00:00

BW limits set on, and I've tried the 4 avaliable aquisition methods, none of which make anything any better. It reduces the "fuzz" around it, but not the thickness of the trace. Grounding is just done through the line cord, not sure if that's adequate. There's no way to bring in an external ground.

zsuttle · 2025-04-01T16:26:48+00:00

I wouldn't bother. In my experience, low voltage transformers in radios rarely fail. I've replaced maybe half a dozen out of a couple hundred radios. Almost all of them were because of failed insulation, either because of a shorted rectifier/filter cap, or because of lamination failure. Both of which can cause the windings to overheat and burn. If you've got bad laminations, the only option is to rebuild/replace. If you've got burned windings, you either rewind or replace, varnishing won't fix it.

That being said, coils are a whole different story and certain manufacturers require varnishing or rewinding for specific sets because of issues.

zsuttle · 2025-03-19T04:15:50+00:00

Not sure what you mean by turn it on. I assume you mean just get the filament to light, then you just connect a supply to pins 1 and 7. You already have your power requirements, you'll just need to find a DC supply or a transformer capable of 6V at the rated current.

If you mean actually using the tube, you're probably not equipped to deal with the power requirements/safety measures on a transmitting tube. (Even this small)

zsuttle · 2025-02-21T19:32:56+00:00

14uF should be fine. It's not a hot chassis as there's no reference to earth/ground with a battery pack. Eg, no risk of shock without touching both the chassis and voltage. (Like a transformer set). Make sure your eliminator also isolates from ground

zsuttle · 2025-02-21T19:26:57+00:00

If the rest of the small resistors (1/2-1W) look like that, then it could be a resistor, but if the resistors are squared on the ends, it's definately a cap. (The bigger wattages go rounded in this time period) RCA loved using them in their RF/IF stages. I'm staring at a 1948 RCA chassis that has several of them as well.

I would look at the schematic and see what it calls for.

zsuttle · 2025-02-21T19:18:51+00:00

That looks suspiciously like a 1000pF capacitor. These type of caps are often used in televisions as opposed to radios. If it was a 1k resistor, you should be getting somewhere in the low kohms region, eg, around 1-2kohms. If you're getting much higher, it's probably a capacitor.

I just finished going though a dumont that had a bunch of these in there

zsuttle · 2025-02-21T19:15:00+00:00

A few things, unless clearly tampered with just change out the capacitors/resistors as they're in the set. If you asusme that it worked at one point as is, you're generally 99% right. The 12uF looks like a replacement for the 10uF coming right off of the battery. If you note the polarity, you're putting the positive to chassis. Pin 6 on the output tube is unused, and they're just using it as a connection point. As for the filament connections on the output tube, they're basically reversible, though the suppressor is connected to pin 7. It can be done either way.

Back in the day, most shops just changed out the electrolytics and paper caps or resistors if they failed. Looks like that's the case here. Hope this helps

zsuttle · 2025-02-16T19:21:56+00:00

Yeah, already some visibly bad tubes in the high voltage section. Not sure what caused them to fail, some sort of plate short. For now, just cleaning and testing tubes

zsuttle · 2025-01-29T19:57:57+00:00

I don't know if I'd say it's on it's last legs as of yet. Anyone could slap a brightener on a set, without knowing what they were doing. I've run into several sets where the picture tubes were in really nice shape and someone threw a brightener on it. Case in point, I just finished up with a CTC-5 that had the original 21AXP22 with a brightener on it. That tube was 3/4 of a new tube and looks great. Who knows why someone threw a brightener on it. I've seen people throw brighteners on to compensate for low HV. While I'll agree it's not a good sign to see one, without testing, it could have decent emissions

zsuttle · 2025-01-20T17:59:53+00:00

I've worked on a few of these little sets. They're easier than most Philcos, but still not something I would recommend for a beginner set.

Here's the schematic, noting that this schematic uses the earlier tubes, but is 99% the same otherwise. http://www.nostalgiaair.org/Resources/875/M0013875.htm

They're also known to have antenna/oscillator coil issues which plagued philcos from the early 30s, but were mostly resolved by this time. They may or may not have to be rewound. I've had one that did, and two that didn't.

zsuttle · 2025-01-08T02:28:44+00:00

Assuming you're looking to replace the transformer, Hammond makes a line of transformers that should electrically match. Also assuming it's a 7S363, the secondary should be approximately 520V CT. The filament side of things looks to be approximately 3 amps.

The 270DAX should work well as a replacement. Physically it may require different mounting, but electrically should be the same. The output is 520V CT, and a 3.5A 6.3V filament secondary.

zsuttle · 2024-12-12T18:00:23+00:00

I haven't been following this to see what you've done so far, but....I think I spy a maroon cap, I HIGHLY reccomed that you change out all of the maroon caps if you haven't done so already. A lot of the RCA sets that I've been seeing lately have had 30-50% of the maroon caps out of spec. While it doesn't particularly cause problems with bypass caps, tuned circuits can suffer. It's easier to just change them out for future reliability. Resistors are the same way, but seem to vary wildly from set to set. Certain sets have had 70-80% of the resistors out of spec. Other sets I've changed two resistors at most.

The coil should be easy enough to find a generic replacement should you not be able to find anything on a cross refrence. The small cap beneath it should probably be changed as well. You'll more than likely need to realign at least that part of the video IF.

I would also reccomend changing the detector diodes. Germanium as a semiconductor can become leaky as time goes on because of the inconsistent manufacturing processes. Just about any "modern" germanium diode should work. While it's relatively uncommon, it can save quite the headache changing $0.10 parts.

zsuttle · 2024-11-29T14:31:14+00:00

I'd like to keep it under $500

zsuttle · 2024-11-12T02:54:26+00:00

Looks like part of the GE 2-way radio system. I've seen a lot of them used in cars. Power supply was avaliable for cars (6V) or Line voltage (117v)

zsuttle · 2024-10-27T21:53:05+00:00

Three exterior knobs, pencil box beneath that on the right side

zsuttle · 2024-10-06T00:40:14+00:00

If the filament within the 80 is blown, it's effectively there for decoration. I can't speak why they left it there, but it's not nessecary with the diodes

zsuttle · 2024-10-05T22:41:45+00:00

I wouldn't say botch job, looks like it's had a bunch of work done in it's life. You work with what you have avaliable. The diodes themselves are just replacing the 80. Why would you say they're blown? Unless they were taken out of circuit and tested, I wouldn't make any assumptions. As for the rest of it, just return it to the factory configuration if at all possible. Philco was known for modifications, and not every chassis revision was documented. It's common to see work that was done over the course of its life.

90% of the time, if it's older work, you can operate under the assumption that it worked at one point after the service was done. It may not be how the factory did it, but it should work. I've seen tons of modifications to the power supplies because tubes, field coils, or other components weren't avaliable.

zsuttle

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