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Philco 60 coil problems - Printable Version

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Philco 60 coil problems - Roger Cole - 04-04-2014

Hi All,

I'm relatively new to radio restoration, and I just started working on a beautiful Philco Model 60. My other previous experience with Philco was restoring a 37-610 which had been in my wife's family.

Looking around the chassis, I've noticed that the 0.7 Ohm police band section of the antenna coil is open, as is the 3.4 Ohm section of the oscillator coil. I understand that these are fairly common problems. The 1st IF transformer also appears to be a mismatched replacement.

A few questions I was hoping someone could help me with:

1. The cans appear riveted to the chassis, but the coil separately bolted beneath. Am I able to simply remove the coil from below without grinding out the rivets?

2. I've been reading that there is a nitrocellulose insulation layer between the primary and secondary coils that is the root cause of the coil breakdown. Should I plan on replacing this? Any suggestions for material?

3. The first IF transformer has been replaced with a more modern 455 kHz IF can. This one seems to have caps built into the can, but the leads still run to the compensating caps on the chassis. I'm fairly sure I can make it work one way or another, but are there any sources for original parts? This appears to be the only replacement part in the entire radio, and the purist in me would like to see it complete.

Any other tips or tricks for coil repair would be greatly appreciated!

Thanks!

Roger

RE: Philco 60 coil problems - PAradiogeek - 04-04-2014

Welcome Roger,

You can definitely remove the coils by removing the screw that holds it to the chassis from underneath. Don't drill out the rivets.

I believe you have your information correct as to the cause of the open coils. I have heard of people using Teflon tape, and even double-sided masking tape. The double-sided tape is nice because it holds the wire down as you are winding the coil.

Not sure about your last question. I'll leave that for someone else.

Good luck!
Jon

RE: Philco 60 coil problems - skyscraper - 04-04-2014

Welcome to the Phorum!

I used a strip of plastic blister packaging material at Gregb's suggestion, it worked very well. It's the closest to the original plastic, and in my extremely finicky radio made a difference over the other insulators I tried. Teflon tape is very hard to work with at small wire sizes.

Good luck!
Will

RE: Philco 60 coil problems - Roger Cole - 04-09-2014

Hi Guys,

Thanks for all the suggestions. I just got her aligned, and so far so good. Here are a few things I noted:

1. The antenna coil for the police band is wound counterclockwise as seen facing the lugs, starting at the far end and ending at the lug end. I used 7 turns of 30 gauge wire.

2. The oscillator primary is wound clockwise as seen facing the lugs, starting at the far end and ended at the lug end. I used 19 wraps.

I scoped out the lugs and coils, and I can post notes if anyone is interested.

3. Someone replaced the first IF transformer with a stock 455 kHz can. They had bypassed the trimmers in the chassis and the trimmers in the can had enough adjustment to tune 460 kHz. It might be nice to have an original, but for the moment, it's working.

4. The set aligned nicely, except that I seem to loose a little selectivity at the high end of the frequency scale. Not a major problem, but I would be curious to hear some thoughts on this.

5. When I aligned the broadcast band, the dial for the police band was off by about 200 Hz. This is a later model 60, and there isn't a separate police band padder. I'm not sure there is much to do about this, or that it really makes an appreciable difference.

Thanks for the encouragement! The cabinet still needs work, and I'll post some pictures when it's done.

Roger