Some years ago there was a splat whilst the set was running and then silence.

The primary of the 2nd I.F transformer has gone open circuit and would be impossible for me to rewind.

Would anyone have such a IF from a defunct set ?

Or even a surplus chassis with the IF would be an alternative.

Happy to offer whatever to pay for the same and postage to Bathurst N.S.W.

Thanks

Hi,
can you post a photo of your chassis?

Sometimes the open happens right at the solder lug junction with the very fine wire of the winging. Because of corrosion from old solder flux. If that's the case, you could repair the open with a short piece of wire (like a resistor lead). Or if you can't repair it, and if the IF can is bigger than most, you could hide a smaller IF transformer inside it. Just be sure it's the same frequency, ie, 455kHz, or is it 262kHz or some other. Other than that, IF transformers for tube radios are quite similar, enough to work well.

Alas no, checked out the fly wires very throughly. It is a o/c deep inside the windings itself.

A substitute of the correct frequency could be put in, however hopeful someone somewhere might have a junked set that could be scavanged.

Just in case it is not marked anywhere, the IF is 175kHz in this radio. It doesn't get a mention on the circuit diagram.
Harold

Thanks Harold, yes it is a 175kHz IF which is not common for broadcast sets.

Hi Simplex, I have some junk portable chassis,
don't know their intermediate freqs for each one,
but can phtograph, and then optionally send some of the parts (don't want any money other than postage).

If you can photobucket an image, you can link that here by yourself.

Thanks, have sent a couple of photos to admin and hopefully they will pop up in due course.

The 513 is a cabinet radio, not a portable.

That's why photos help

I have at least two console chassis to harvest for parts,
and I cannot keep this all.
The almost bare chassis' will eventually have to go in the bin anyway.

Again, I don't know their intermediate freq,
but maybe someone else can help with that,
the ones I know are Philips, AWA, Tasma.
Some portable ones could still fit.

The tuning dial on a very similar Airzone, the 514, once featured in the title image on this website.

Do dismantle the old one. There are three common things that open a primary on an IFT.

One is soldering & movement, often changing components (common).

Two corrosion at the solder lugs, can be repairable.

Careless adjustment of top trimmers. The primary trimmer is alive on a top trimmer and is easily shorted to the can: That can burn the coil.

The nut in the centre top releases the former from the can and the can is able to be raised to see the internal connections after its retainers are removed. That if done carefully avoids unwiring. There is an art to getting it back together. Sewing thread is involved, not rope.

Marc

Wow, Mine are definitely not that clean, and all round.

Had spent some time inspecting the I.F after the failure which occurred about a year after doing some repairs.

Actually few components were changed, only a cap or two.

Tried resoldering the tabs but no success, the o/c is deep in the winding.

Thanks for the offer of replacements Art, would you have the model numbers of the chassis that are there ?

So that the I.F frequency can be identified.

Kicking myself for not taking photos of the IF while it was in pieces.

Have put the whole radio back into the cabinet.

Edit: the 513 chassis has a removeable plate on the chassis which obviously is for a power transformer.

Guess the same chassis was used for the mains version.

Would anyone know the IF frequency of the mains version by chance ?

In case a mains chassis comes my way.

Thanks

All the Airzone mains-powered models for 1937 I.F. frequencies are 456kHz. It appears that only their battery powered models for that year used 175kHz.

Thanks Mono', thought that would be the case.

This restricts options greatly I think, even beginning to wonder whether a rewind would be an option.

Although rewinding such a coil would take a high degree of skill as the wire is wound in a particular manner which I don't think would be easy to duplicate.

Have to ponder about it for a while.