Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 60 coil problems
#1

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
#2

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
#3

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
#4

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




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco Model 80 Transformer resistance
Just forget this number, it is useless anyway. Simply proceed with your project.morzh — 10:08 PM
Philco Model 80 Transformer resistance
My $0.02 is that it is a misprint. I tried to look up the value for the similar 84 and 37-84, and ther is no resistance...MrFixr55 — 09:51 PM
Philco Model 80 Transformer resistance
Thanks for the quick reply! Hmm...well that's good, so what am I seeing that's 1042 ohms on the schematic for the pow...Mike L — 08:46 PM
Philco Model 80 Transformer resistance
The DC resistance of the primary is 8 to 9 Ohm.morzh — 07:54 PM
Philco Model 80 Transformer resistance
I have a feeling the primary winding on the power transformer is bad. My resistance reading on the primary side is 9 ohm...Mike L — 07:48 PM
Rusty Tuning Condenser
I would try Naval Jelly and use a soaked pipe cleaner to get it where it needs to go.RossH — 06:56 PM
38-10T chassis Restoration begins
Hello Dconant , they sold mica to use as a insulator between transistors and their heatsinks too. Rob I will remove th...radiorich — 02:52 PM
38-10T chassis Restoration begins
Thanks for the info guys. I always wondered why the use of mica. Now I know.dconant — 01:52 PM
38-10T chassis Restoration begins
Most common plastics have a dielectric constant in the 3-4 range whereas mica is around 6. This means that even if you w...Steve D — 01:46 PM
38-10T chassis Restoration begins
It is acceptable but not desirable. Plastic is not an approved cap dielectric, and even though a reasonably thick piece...morzh — 11:52 AM

[-]
Who's Online
There are currently 3681 online users. [Complete List]
» 1 Member(s) | 3680 Guest(s)
Avatar

>