[markmokris]

I am working on a Philco Model 80 Junior, and I have a couple questions about the oscillator coil, part number 8.

I measure continuity among pins 2-4-5, and between pins 2-4, and between pins 4-5.  The tickler coil, pins 1-3 is open.

   

   

I pulled the coil out of the radio and removed the tickler portion.  My question is about the primary and secondary.  The outer coil appears to be larger wire, maybe 50 turns of 32 ga wire.  It is wound on top of an inner coil or much finer wire, maybe 150 turns of 38 ga wire.  This is all a guess.

The outer coil seems to be wired to pins 5 and 4.  It measures 5 ohms.  The inner coil is wired to pins 2 and 4.  It measures 17 ohms.  This resistance measurements don't match the schematic exactly, though relatively, 5 ohms is close to 2.83 and 17 ohms is closed to 24.

Question 1. Based on the resistance readings, doesn't this seem to indicate that the outer coil is the primary (left side) and the inner coil is the secondary (right side)?  If that is the case, the coil is wired into the circuit backwards!

I am hoping someone has enough familiarity with this coil to help me make a judgement.  What is wierd  is that it appears to be original factory connections, not messed with. But who knows?

Question 2. Also, the tickler coil appeared to be 18 turns of maybe 34 ga wire, wound counter-clockwise looking from the bottom of the coil.  I think that is what I observed.  But my mind is playing tricks on me at this point.  (I know, I need to be more careful).  Does anyone know this tickler winding?  Can you confirm?

Thanks!

Mark K8KZ

[Crist Rigotti]

Here are some links that might be of some help:

http://www.philcorepairbench.com/tips/svctip36.htm

http://www.philcorepairbench.com/tips/svctip43.htm

http://www.philcorepairbench.com/tips/svctip03.htm

http://www.philcorepairbench.com/tips/svctip44.htm

Yes, the primaries are on top of the secondaries. The secondaries are the coils wound directly on the coil form.

[markmokris]

Crist,

Thank you. I have pretty much read through those service tips and plan to make some of the suggested mods. I appreciate your comment about the primaries /secondaries.

Is that pretty much the case on most of these coils? The primaries are on top of the secondaries?

Thanks,

Mark

[Crist Rigotti]

Mark,
I have limited experience with radio restoration but I do think with Philco coils, the primaries are on top. I'm sure Ron and others who do have a lot of experience will weigh in.

[markmokris]

I just looked at the parts list for the Model 80 and it lists the secondary at 2.4 ohms not 24 as shown in the schematic. This confuses everything. Now I am not sure which side is the secondary, the inner, thinner winding or the outer thicker winding?

And is it a problem that I am measuring 17 ohms between pins 2 and 4? I don't know which winding that matches.

Ron, Chuck, Terry, anyone...would you know which winding is which?

Thanks,

Mark

[klondike98]

if you get a magnifying glass, sometimes you can see the wires and sort out which winding they are from.

[markmokris]

if you get a magnifying glass, sometimes you can see the wires and sort out which winding they are from.

Bob,

I get your point, but I CAN see the wires.  The question I am left with - There is a bottom winding with fine wire, and a winding over it with thicker wire.  Is the bottom winding with the fine wire the secondary or the primary?

It is wired into the circuit as the primary.  It seems the ohms measured is closer to what it should be for the secondary on the schematic.  

I'll will probably try it both ways.  It just is a matter of flipping two wires.

Thanks,

Mark

[Radioroslyn]

Hi Mark,
 The small winding at the bottom is the tickler or feedback winding. The others you need to not be concerned with as they are still good. Don't rewind them . They are frequency determining and are some what critical in terms of inductance.

Terry N3GTE

[markmokris]

Hi Mark,
 The small winding at the bottom is the tickler or feedback winding. The others you need to not be concerned with as they are still good. Don't rewind them . They are frequency determining and are some what critical in terms of inductance.

Terry N3GTE

Thanks Terry.  I really appreciate all your help.  I think I am not being clear with my concern.

Aside from the tickler, once I pulled out the oscillator coil I see two good windings.  The inner one is the higher resistance winding and its resistance matches the values that the schematic specifies for the secondary.  Except that winding, the inner one, is wired into the circuit as the primary.

But isn't the inner higher resistance winding supposed to be the Secondary?  I am concerned it is wired wrong.

Maybe I am just overthinking this.

Thanks guys,

Mark

[Radioroslyn]

< Maybe I am just overthinking this.

Methinks so.

Terry N3GTE

[markmokris]

She's working great! I am using about 2 feet of antenna wire, and I am tuning in stations across the band with excellent volume. I adjusted the regeneration throttle condenser as directed, and this did have the affect of peaking the performance.

I am tempted to not even try some of the additional performance tips at the Philco Repair Bench. I tried the gimmick capacitor but that just seemed to degrade things. I thing I will leave things as is.

Thanks for all your help everyone!

Mark K8KZ

[klondike98]

[Radioroslyn]

Hook it to your 160mtr dipole and it will really pick up. One note it's important that the chassis is grounded if not it may cause the volume control not to work properly.

GLOM
Terry N3GTE

[markmokris]

Thanks again guys. 160 meter dipole. You live on some property, huh Terry?

I gotta pull out my ham gear one of these days and set it up. I'm too busy fixing up these old Philcos.

Mark K8KZ

[Radioroslyn]

Nah, I've got a 100'x60' lot. Have a 80mtr dipole up it's more like a vee on it's side apex at the front of the property and the legs run down side of the lot. Up about 35'.

Terry N3GTE