Looks like nobody's chiming in. If you were turning the IF adjustments with the oscillator dead, there will be no IF signal for the adjustments to 'peak' to. So they're probably 'waay outa whack. To get them back on peak, inject a 456 khz signal. Keep attenuating the level as needed as they approach the peak. Once on peak, attenuate a little more and get it as sharp as possible.

Then start looking for why the osc. isn't running. For a start, check for continuity of the osc coil's primary and secondary windings.

Well that's the thing it was "working" (I was able to inject a 456 kHz signal into the radio and it was picking it up but it was intermittent) and now when I try to inject a 456 kHz signal into the radio it won't pick it up at all period.

Although I think I figured out part of my problem, my temporary "A" battery rig is only putting out about 150 mA of current and the radio's filaments require over 500 mA of current. So I think I need either brand new D-Cell batteries or some high output current rechargeable D-Cell batteries (like some 10,000 mAh NiMH rechargeable batteries.)

As for the oscillator coil measurements goes, I tried measuring it with my multimeter and all I get is an O. L. Reading on my multimeter when trying to measure it, it's the same way with the antenna coil and the IF coils as well and I'm pretty sure there's no way that both IF coils and the Antenna Coil and the Oscillator coil could of died all at once especially seeing as when I first got it and took it apart and measured everything they all tested fine then...:scratch2:

i'd wait for the caps and replace them before worrying about anything else.

OK so a little update on this radio, I got the radio recapped yesterday and I also got a set of 2500 mAH NiMH rechargeable D batteries from Harbor Freight and then a Charger for them at Menard's (they were the only place near me that had a universal battery charger in stock without having to travel to Mishawaka or South Bend which is over a half hour away from me.)

And I charged the batteries over night and installed them into my battery clip and turned on my radio with my signal generator hooked up to the antenna wire and sure enough I was signal through (albeit at the wrong frequency, it was coming in at 453 kHz rather than 456 kHz) and so I realigned the IF cans so that they were coming in at 456 kHz instead.

But then shortly after that the radio faded out and I checked my D batteries for my "A" supply and they were still putting out a charge so then I turned the radio back on again and the radio started working again but then it faded out again.

Also something I've noticed with my radio is that one of the IF cans on this radio is a replacement and when I would power on this radio and once it warms up, the radio makes a short burst of white noise and then it goes away like the radio is trying to pick some stations or trying to function but it can't quite function properly.

Also another weird thing I've noticed about this radio is that this radio will only operate at between 2.2 volts and 2.4 V on the filaments, if I try to use the recommended 2.1 Volts, the radio won't operate.

Any ideas as to what might be going on with the radio?

First of all, a fully charged 2 volt lead-acid puts out 2.2volts. This voltage is what the radio was designed to use.
Did you check the tubes on a good tube checker. You probably have a weak osc-mixer tube. Increasing the filament voltage, will increase the emission.

I was using a set of 1.2 V NiMH rechargeable D Cells, not the 2V Lead-Acid battery I had previously linked here and asked about.

Secondly I don't have a tube tester capable of testing the old style 4, 5, 6 and 7 pin tubes, so I can't check the tubes unfortunately.

I've tried to acquire one but everytime I find one they usually want over $100 for it, which I can't afford anything like that right now.

Since your set has AVC why not monitor that voltage to get a handle on what's going on? You'll want to use a VTVM, a scope, or a digital volt meter connected to the bottom side of R3(2meg). When the set is working does your AVC voltage seem to work normally with and without a signal tuned in? AVC voltage normally will be negative with a strong signal and become more positive as you de-tune the station. If the local oscillator isn't running you loose AVC action. If AVC voltage continues to respond to tuning then when the audio fades, then most likely you have an issue in the audio sections. When the radio is working correctly you can also align the IF's to the most negative voltage on the AVC line. There's really no need to rely on listening to an audio tone through the speaker.

Edit R3 not R4

I meant AVC voltage at bottom side of R3, not R4 as I fist posted.
Edited above post.

;) Looking at the tube compliment posted in your first post , I can not believe a pair if D cells in series is anywhere close to powerful enough to light all those filaments .

We didn't chime in because the OP was waiting for the parts.

They are 2500 mAh batteries, so more than enough juice to power the filaments (the filaments require around 540 mA).

Well I got the parts in and installed, and its looking like I might have a bad 1C6 tube which can be subbed out for a 1A6, 1C7 or a 1D7, whichever is more readily available.

Does anyone on here have either a 1C6, 1A6, 1C7 or a 1D7 tube that is known to be good that they could send me, or know if there are any for sale on fleabay for sale for relatively inexpensive?

Thanks!

UPDATE: I found a set of NOS Ken-Rad 1C6 tubes on feebay for $16 plus shipping.

UPDATE: I figured out what my problem is, its the IF Cans, apparently at some point in time in this radio's history both IF Cans were replaced, and whomever did the replacement installed two IF Cans of with two Different IF Frequencies that were completely different from the original IF Frequency of the radio! :nono: :no:

The 1st IF Can was replaced with an IF Can with an IF Frequency of 455 kHz and the 2nd IF Can was replaced with an IF Can with an IF Frequency of 475 kHz, and the radio's original IF Frequency according to the Riders was 465 kHz which might explain why this radio isn't working right.

When I feed a signal through my antenna hookup on the radio using my signal generator I can hear the signal coming through albeit very faintly (I have to have the volume turned clear up to hear it) and with the signal Generator's High Output signal being used the signal comes through at a somewhat normal volume level, which means that what my radio's problem is isn't the tubes or a dead oscillator coil or too weak of batteries, what the problem is, is the radio is trying to operate with two IF Cans of different frequencies.

So I'm not quite sure how I would fix this issue...:sigh::scratch2:

It should be possible to align the IF cans 10KHz off designed frequency. Nothing to loose trying it. If they don't peak in range of adjustments you could try tacking pF caps across windings to see if you can get more range.

Well what's interesting is that the 1st IF can's IF Frequency is 10 KC lower than the original IF Frequency, and the 2nd IF can's IF Frequency is 10 KC higher than the original IF Frequency of 465 kHz, which I'm not sure what the point of that would of been but its kind of bizarre.

And I guess I can see what happens as far as trying to align the IF cans to the original 465 kHz IF Frequency.

It's unfortunate that the owner of ESRC passed away.
They had those odd-ball tubes reasonable. :thmbsp:

Yes it is unfortunate. :sigh:

I did check the voltage at the AVC line resistor (R3) and it does respond like its supposed to but the audio is not very loud unless I use my signal generator's "HI" output connection, and then it comes out at a more "normal" volume level.

I have attributed that fact to what I believe is a faulty 1C6 Tube, because the oscillator seems to be "running" but not very well, and both 1A4 tubes respond with a hum when I touch their grid caps but nothing when I touch the grid cap on the 1C6, I get no hum out of it.

So I'm thinking I'm on the right track and just about have this thing going.

Did you peak both if transformers to 465 khz?

jr

Yes I did, and when I would try to inject the 1400 kHz signal in through the antenna leads so I could work on the dial tracking/alignment I can barely hear the signal generator coming through at full volume using the attenuated output signal at 50% output (the highest amount of output that my signal generator can do), but then the unattenuated output allows the signal generator to be heard at a somewhat normal volume level.

OK so a little update, I got my NOS 1C6 tubes in today and my radio is now mostly working, it is now definitely oscillating (I did the holding another radio up next to it trick and that second radio was picking up this radio's oscillator signal).

But its still not picking up any stations unfortunately.

I've got the IF cans Aligned to 465 kC the Best I can (seeing as neither of the IF cans in this radio are original to this radio and are not 465 kC cans).

So I'm kind of not sure where to go from here now.

Here's a video showing what the radio is currently doing:

https://youtu.be/e702udS6aiM

OK, so another Update, it seems I had a bit of a dislexic moment because this radio's IF Frequency is 456 not 465 like I had been saying the entire time...:stupid: :eek:

Anyways So I realigned the radio to 456 KC and the tuner seems to be working better with the signal generator, but its still not picking up any stations on its own with a long wire antenna hooked up to it... :headscrat

So I'm wondering if my 30 Tube is bad as well because that tube controls the Second Detector and the AVC circuit which the AVC is working as it should be but I'm wondering if maybe the detector portion of the 30 tube is bad or at least not in very good shape.

Anyone here have a known good 30 tube they could spare me? If not I guess I could get one from ebay.

The 30 tube is a single triode configured as a grid leak detector. Notice the plate tied to ground. Since you say you have AVC voltage changes you can be sure the 30 is working. Can you see AVC voltage change when tuning on and off a known local radio station? Make sure C8 is .0005uf. If it's too large it will start filtering the audio.

No there is no change in the AVC voltage when trying to tune in a known local station. In fact trying to tune anywhere on the dial the AVC voltage stays pretty constant at around positive 15 mV and doesn't go negative at any point when tuning across the dial with just a long wire antenna attached.

It does however work when using the signal generator but like I said previously I have to use my signal generator's unattenuated high volume output signal output in order for the radio to be able to pick up the signal from the signal generator and be able to affect the AVC voltage.

So I'm not sure what's going on here.

Did you see the video I posted of my radio and what it's doing with just an antenna hooked up?

What you say indicates is that your local oscillator is either not running, or it's running at an incorrect frequency.

When you inject an IF frequency from you signal generator you are forcing the correct signal through the IF transformes, which in turn gets detected by the 30 tube and produces AVC voltage. The key here is you're not relying on the local oscillator to mix with the incoming rf signal to produce that outcome.

In normal operation the rf signal mixes with the local oscillator to create beat frequencies equal to the sum and difference of the two. One of those beat frequencies is the IF signal. You should double check that you didn't replace a cap around the 1C6 tuned circuit with a incorrect value and also verify the two winding's in the oscillator coil(#17484) have continuity.

What is the other radio's dial setting when it picks up the Coronado's oscillator? And what is the Coronado's dial setting? The diff between the settings is the Coronado's IF frequency (assuming both radios' dial calibrations are reasonably correct).

For example, if the Coronado's dial is at 550, its oscillator should be heard around 1010 on the other radio. Or if Coronado's at 1140, you should hear the osc at about 1600.

Well I checked all of the original "dogbone" resistors in the radio (which are all 1/4 watt resistors according to the service manual) and they are all within spec.

When I recapped this radio, I used orange drops for all but 2 of the capacitors, (the 2 capacitors that I didn't use orange drops on were the .0005 MFD 600 V caps that I had to use Silver Mica caps for because they didn't have any orange drops that went down that low in value), and I made sure that I put the caps in the right spot, so I don't think its the caps or the resistors.

When I first got this radio (and after I realized that someone had attempted to wire a power cord to the antenna wire terminal strip) I had tested the antenna coil and the oscillator coil to make sure they weren't damaged, and they both tested fine.

But then when I was checking voltages around the power switch (where the battery wires wired into the switch), I had accidentally let out some magic smoke but I couldn't tell where it came from, but all I know is that ever since then the antenna coil and the oscillator coil have been reading O. L. on my multimeter, and I'm not sure why because the coils don't look burnt and they don't look damaged either.

Do you need some pictures of the underside of the radio so you can see what the radio looks like underneath and see if you can see anything out of place?

Well if by O.L. you mean they are reading infinite ohms then I think you've found a problem. Those coils should show a fairly low resistance.

Well the strange thing is that the Coronado's tuner is set to around 640 AM and the tuner on my Panasonic RF-511 AM/FM transistor radio is set to about the same spot and that's where 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...:scratch2:

Well if by O.L. you mean they are reading infinite ohms then I think you've found a problem. Those coils should show a fairly low resistance. Try putting your meter on diode check and see if you get a beep across each winding. If no you have an open winding, that is providing your meter beeps when you touch the two probes together.

Well I'm guessing this radio is going to have to be a shelf queen I'm guessing, because those coils are probably going to be darn near impossible to find, and I doubt they could be repaired.

Post us a couple pictures of what they look like. I doubt they're anything too unique. What you have there is a very basic broadcast band only radio.

Ok, here's the Oscillator and antenna coils.

Looking at the schematic I'm in disbelief that you opened a winding in both by simply taking voltage measurements. :no:
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.

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.

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.

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

Well I've already sunk about $50 into this radio...:scratch2: