Just picked up a 1930s Battery operated Coronado

[vortalexfan]

Originally Posted by Kevin Kuehn

Looking at the schematic I'm in disbelief that you opened a winding in both by simply taking voltage measurements.
Are you 100 percent positive that both transformers have at least one winding open? Maybe you should post us a couple pictures of the entire bottom side the chassis, just in case you're overlooking something obvious.

These Meissner numbers will replace them. They use to be common as dirt.
14-1010 standard broadcast band antenna coil
14-4034 456kc oscillator coil

I'm sure there's other manufactures numbers that would work, as well as pulling them out of junked radios. The oscillator coil should ideally be for 456kc, but as mentioned you can usually walk the IF's off frequency a small amount.

Well as I had stated previously, both IF cans are replacements, the 2nd IF Can is a Meisner replacement rated to cover the frequencies of 450 KC to 475 KC, and the 1st IF can is a generic 455 KC replacement.

As for the Oscillator and Antenna Coils, I had already removd the Oscillator coil from the chassis and I double checked it and it definitely doesn't give me any sort of resistance measurements all it gives me is an O. L. reading on my DMM, as for my antenna coil it also doesn't give me any sort of resistance readings as well, I've tried every single terminal combination (because I wasn't sure which terminals were the primary and secondary terminals), and I get the same O. L. readings on the antenna and oscillator terminals.

I can get you a picture of the underside but like I said the Oscillator coil isn't going to be there because I removed it.

[old_coot88]

Originally Posted by vortalexfan

...I hear the Coronado's Oscillator on the Transistor radio is at 640 AM on the dial or very close to that spot anyways and when I go up the dial the oscillator noise kind of dies off the higher up the dial the tuner goes (on both radios).

So I'm guessing my oscillator is working but not correctly...

The osc is not running, period. Just a note on basic superhet practice (for convenience, say the IF is 460): When the radio is set up and aligned correctly, the osc will always track 460 on the high side of the received signal. So whatever station is tuned in, its signal will 'beat', or heterodyne, against the osc, generating the Intermediate Frequency of 460 khz, which is then sent downstream, amplified and detected.

Um.. what does O.L. stand for?

[vortalexfan]

Originally Posted by old_coot88

The osc is not running, period. Just a note on basic superhet practice (for convenience, say the IF is 460): When the radio is set up and aligned correctly, the osc will always track 460 on the high side of the received signal. So whatever station is tuned in, its signal will 'beat', or heterodyne, against the osc, generating the Intermediate Frequency of 460 khz, which is then sent downstream, amplified and detected.

Um.. what does O.L. stand for?

Ok, that's what I figured.

O. L. I believe means OverLoad(ed).
Anyways that's just a guess, because every single Digital Multimeter I've ever owned always showed some variation of the O. L. designation for the "infinite" or "open circuit" reading on the multimeter display.

Anyways I think I'm going to need new Osc. and Ant. Coils, or at least an oscillator coil.

[Kevin Kuehn]

Just for giggles does your meter show zero ohms when you touch both test probes together?

I guess you need to make the call of how badly you want to fix that radio. I looked on ebay and see a few 14-4034 Osc coils but sellers apparently think they're setting on the last ones on the planet.

[vortalexfan]

Originally Posted by Kevin Kuehn

Just for giggles does your meter show zero ohms when you touch both test probes together?

It measures 0.3 Ohms when I touch the probes together. Why?

I guess you need to make the call of how badly you want to fix that radio. I looked on ebay and see a few 14-4034 Osc coils but sellers apparently think they're setting on the last ones on the planet.

Well I've already sunk about $50 into this radio...

[vortalexfan]

Originally Posted by Kevin Kuehn

Just for giggles does your meter show zero ohms when you touch both test probes together?

I guess you need to make the call of how badly you want to fix that radio. I looked on ebay and see a few 14-4034 Osc coils but sellers apparently think they're setting on the last ones on the planet.

I just looked on feebay and those coils are only $15 or so, which isn't too bad.

Just picked up one of these Oscillator Coils for $13 with free shipping.

[Kevin Kuehn]

Originally Posted by vortalexfan

It measures 0.3 Ohms when I touch the probes together. Why?

There's always a little contact resistance at the connectors and prob tips.

[vortalexfan]

Originally Posted by Kevin Kuehn

There's always a little contact resistance at the connectors and prob tips.

Yes, which I was aware of, but what does that have to do with your "just for giggles" experiment about my oscillator and antenna coils being bad or not?

[vortalexfan]

OK here's a shot of the undercarriage of this radio.

Is there anything that looks out of place to you guys (besides the previously removed oscillator coil)?

[Kevin Kuehn]

Originally Posted by vortalexfan

Yes, which I was aware of, but what does that have to do with your "just for giggles" experiment about my oscillator and antenna coils being bad or not?

I didn't understand how you'd expect the radio to pick up stations all the while knowing those coils were open. But in the end the important things is you're making good headway.

[vortalexfan]

Originally Posted by Kevin Kuehn

I didn't understand how you'd expect the radio to pick up stations all the while knowing those coils were open. But in the end the important things is you're making good headway.

Ok, sorry when it comes to stuff like that I'm slower than molasses in the winter on the uptake.

[vortalexfan]

OK, so I was looking at the original Oscillator Coil for this radio and I noticed that all of the wires coming from the coil are there and going to their respective terminal except for one, one of the wires is missing coming from the coil to the terminal and the coil has one spot that looks like it was chewed on by a mouse or some other kind of rodent, and I suspect that this may be why this oscillator coil is bad...

Actually scratch that 3 of the 4 wires were broken from the places where they came out of the coil.

UPDATE: Antenna Coil is still good, its just the oscillator coil that was bad, and I think it was chewed up by a mouse or some other rodent.

[vortalexfan]

UPDATE: Still waiting for the Oscillator coil to come in the mail (It had free shipping, which means USPS 1st Class Mail, which means it will probably take its dear sweet time getting here).

But at least its going to be an inexpensive fix and its not going to be a shelf queen like I thought it was going to be originally.

[Kevin Kuehn]

While we're waiting on parts.. back in post 64 I mentioned that the 30 tube is a single triode configured as a grid leak detector, which it is not. I intended to say configured as a diode, notice the plate tied to the cathode(both grounded). When I came back and reread that just now it jumped right out at me. Anyhow I just wanted to make that clarification so as to not confuse anyone else reading along. And you guys should have called me on that one.

[vortalexfan]

Originally Posted by Kevin Kuehn

While we're waiting on parts.. back in post 64 I mentioned that the 30 tube is a single triode configured as a grid leak detector, which it is not. I intended to say configured as a diode, notice the plate tied to the cathode(both grounded). When I came back and reread that just now it jumped right out at me. Anyhow I just wanted to make that clarification so as to not confuse anyone else reading along. And you guys should have called me on that one.

Thanks for the clarification.