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Morzh and Terry,
The two outer pins of the pot measure 26K. At minimum volume, I got a measurement of 26.2 and at maximum I got a reading of .1. This was measured using my digital multimeter set at 200K.
Next, I measured the from the chassis to pins 3 and 4 (6K resistor and .0015 capacitor) of the oscillator transformer. On pin 3, I got a reading of 6.1 and the reading on pin 4 jumps around from negative something to zero (infinity?) almost immediately. I wasn't getting any readings until I set my DMM to 20K.
Also, Terry, I read your PM and I will try to call sometime this weekend.
Dave
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Ok Looks like both coils are open. If you look at the diagram the ant coil is connect across the wiper of the volume control to chassis gnd. If the coil was good the very low resistance would trump the resistance of the volume until you turn the control almost all the way down ( turned down so it would be less that the resistance of the coil) If the coil open (like yours) what you are measuring is only the resistance of the control.
The osc coil again should measure a very low resistance like 2 or 3 ohms. From chassis to the junction of the coil at where the 6000 ohm resistor connects. You can double check the osc operation by listening for it with transistor radio tuned to 470KC above the dial reading of the Philco. Place the transistor near the 6J7 osc tube or osc coil
Both windings are about 25t of 38ga magnet wire. Wire ga is not very critical anything from 32-40ga is fine.
Terry
(This post was last modified: 04-03-2015, 09:50 PM by Radioroslyn.)
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Oh brother. I was hoping to avoid this. Oh well. In any case, I counted the number of turns and made note of the direction and what tabs the wire is soldered to so I can start rewinding the coil. The problem I ran into was the plastic stuff the wire is wound on broke into a bunch of tiny pieces so it might be difficult to make an exact copy.
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The # of turns isn't super critical on the ant coil as it doesn't determine the frequency (the secondary does) And the phase relationship (direction) doesn't matter much as it just for coupling the ant.
The osc coil is a bit different. The number of turns determines the amount of feedback in turn causes the circuit to oscillate. Phase does matter and the # of turns is somewhat critical. Not enough turns will cause it not to oscillate across the whole band. High end will work but as you go lower in frequency it requires more feedback so the osc will quit. Too many turns like 40 or 50 will cause the output of the osc not to be clean.
The little clear piece isn't critical at all. It was part of the problem! If it makes you feel better you can use a thin strip of masking tape. Ron sez to bake the coil at low temp to evaporate moisture out of it.
Terry
(This post was last modified: 04-04-2015, 07:16 AM by Radioroslyn.)
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In the link below I described restoration of a Kirk's radio antenna coil. Look this an a couple of pages before in the same thread.
The material I used was fishpaper, which, upon winding all coils, was coated with acrylic conformal coating.
For the leads I used thicker lead wire from old resistors.
As you have diameter and turns, the rest should be easy. You will spend more time building bobbin than winding turns.
http://philcoradio.com/phorum/showthread...667&page=6
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Do I have to use copper wire for the rewind? I went to a well known electronics store and the only 32ga wire they had was red magnet wire. Not sure how well that stuff holds solder.
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Magnet wire is copper and is what you want to use. The enamel insulation is very thin and can be removed with a match or your soldering iron.
--
Ron Ramirez
Ferdinand IN
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If you do have trouble getting the solder to stick just scrape the wire gently with a sharp knife to remove the green coating.
Terry
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Exacto works well, scrape away from yourself, holding the blade edge towards youself. Press lightly.
Or fine grit paper.
Or quick swipe through a lighted match with immdiate dip in alcohol.
Then tin it.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Ok, I have a problem. Everything I have read says both the oscillator and antenna coils have only a handful of turns. The oscillator coil I have has 91 turns of one wire and 14 of the other. The antenna has 152 and 19. Both forms themselves are made of plastic, maybe bakelite, not cardboard as I would have expected from an older radio. In any case, the other radios I have restored appear to have coils made of cardboard. Anyway, I rewound both coils and, needless to say, the radio still doesn't get reception. I am right now searching for info on the antenna coil part 32-1310 and oscillator coil part 32-1311 to determine the exact and correct number of turns for both. Would anyone venture to speculate the I.F. transformer is bad which could be the cause of no reception?
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I'm sorry perhaps I wasn't clear. The only windings we are discussing are the two small ones, the ant primary 19t and the osc coil tickler or feedback 14t. Typically the secondary winding are ok. Those would be 91 & 151t jobs. Also those determine the frequency of the osc and input of the mixer. Don't really want to mess with that if you don't have to.
The original form are bakelite and not cardboard like what Mike was working on. ( This is a Philco not a Silvertone cheap cheap set)
So what did you rewind? both pri and sec on both??
Terry
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(04-06-2015, 08:06 AM)Radioroslyn Wrote: The original form are bakelite and not cardboard like what Mike was working on. ( This is a Philco not a Silvertone cheap cheap set)
Which does not mean that, if made of fishpaper, they would not work. Especially considering that, if crumbled, there is a little chance you will be making one from bakelite again.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Oops. Yes, I did both the primary and secondary on the ant and osc.
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Boy your a busy little bee! HaHa.
When you rewound the osc coil did you wind both coils in the same direction?? Doesn't matter which way. You might try taking a listen for the osc at 1570kc with the 84 at 1100kc.
Terry
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Just looked at it again and I see I went opposite ways. So, I am going to pull my hair out and bang my head against the wall a few times in hopes of making by brain click into action and attempt to fix this blunder. Why oh why didn't I ask the simple question which wire do I rewind?
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