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Model 60B late antenna coil question
04-29-2012, 06:16 AM (This post was last modified: 04-29-2012 06:21 AM by jth877.)
Post: #1
Model 60B late antenna coil question
Been working on a late 60B w/ square tube shields. Recapped the set and replaced all out of tolerance resistors. I had to rewind the antenna primary (4 turns) and the outside oscillator winding (counter clockwise, 17 turns). The set is running, but either something else is wrong of it's WAY out of alignment. I can only pick up the station I broadcast thought my sstran (volume is mediocre even when turned all the way up) and can barely pick up anything else using a 6ft wire.

I read in a previous post while searching for coil info, that the antenna coil has a 20 turn section between lugs 2 and 5. Mine measures open. Is this the section directly under the 4 turn outer section?

What I found by Ron:

Re: Philco 60 - Problem with Short Wave/Police Band
I see I never did report back with the correct number of turns in the 60 oscillator coil primary - my apologies.

I'll give details on both coils while I'm at it.

Model 60 Antenna Coil

Primary (outer) winding - 4 turns, CW, bottom to top, 38 gauge
Secondary winding (on the coil form) - All CW, bottom to top. 25 turns from beginning (lug 1) to lug 3. 129 turns from lug 3 to lug 2. 20 turns from lug 2 to lug 5. 32 gauge works well for this winding.

There is also a separate winding inside the coil form, mounted at the top. It is approximately 250 turns, 38 gauge.

Model 60 Oscillator Coil

Primary (outer) winding - 18 turns, CCW, 38 gauge, bottom to top, lug 3 to lug 2
Secondary winding (on the coil form) - All CW, bottom to top. 15 turns, lug 1 to lug 4. 90 turns, lug 4 to lug 5. 22 turns, lug 5 to lug 6 (on top). 32 gauge is OK for the secondary.

To determine which lug is lug 1, 2, 3, etc., hold the coil by the large mounting lug and count the small lugs clockwise from left to right.
--
Ron Ramirez
Ferdinand, IN
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04-30-2012, 03:27 PM (This post was last modified: 05-01-2012 02:36 AM by jth877.)
Post: #2
RE: Model 60B late antenna coil question
Update: I found more resistors that were way out. Funny, some of them were over 20% under value. Anyway, I aligned the set by ear and it is performing much better. With a 3ft wire in my basement I can pick up the 4 or so strong stations in my area and the shortwave has popped to life.


*EDITED*
That means the information in in the quote from Ron is CORRECT
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04-30-2012, 09:49 PM
Post: #3
RE: Model 60B late antenna coil question
No, jth877, my information is correct - you are incorrect, and I will prove it.

First, let's look at a Model 60 antenna coil as shown on a Model 60 schematic.

[Image: 60_ant_coil.jpg]

I have numbered each terminal of this coil on the partial schematic above. Notice there not only is a winding between lugs 2 and 5, but if there were no windings between those two lugs, the set would not play unless someone connected the lead to the tuning condenser and 6A7 control grid to lug 2 instead of lug 5. And then, its performance would be iffy at best.

To reinforce this thought, here is a crude illustration of the bottom view of a Philco model 60 antenna coil.

[Image: 60_coil_pinout.jpg]

Looking at the bottom side of the coil, where the lugs and mounting bracket are, you count the lugs clockwise starting at the first lug to the left of the mounting bracket, as shown above.

"Top" is a terminal on the very top of the antenna coil, not shown in this crude illustration.

"GND" is the mounting bracket itself, which also has a lug connected to it. The coil will be grounded by the mounting lug and the bolt which secures it to the chassis (ground).

--
Ron Ramirez
Ferdinand, IN
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05-01-2012, 02:53 AM
Post: #4
RE: Model 60B late antenna coil question
My apologies you are correct! I was counting the ground lug as Lug 1. So I was looking between lugs 1 and 4. Now it makes sense. I wish I found a diagram like that when I started working on this thing. At least someone will find it if they search in the future. Maybe a new topic for the website? Problematic coils and their respective schematics?
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