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The original Philco speaker used was K-7 (or K-21 in later models). But you can use any K series speaker with an 1125 ohm field coil and by adding the proper output transformer to match a 7100 ohm impedance plate load to a 1.25 ohm voice coil.
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Ron Ramirez
Ferdinand IN
Posts: 7,288
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City: Roslyn Pa
Since your spk is rebuilt just for grins you could put a 2K 10w resistor in parallel w/ the field coil. This will get your voltage up but will limit the current that passes thru the coil so it may have less magnetic pull. The higher the value the more current passes thru the coil but the more voltage drop.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 34
Threads: 6
Joined: May 2017
City: Huntington, WV.
Posts: 34
Threads: 6
Joined: May 2017
City: Huntington, WV.
...and thank you Terry! I might just give it a whirl. The field coil reading is at 5.9k. So if I put a 1.5k in parallel, it should get me close to the number I am looking for.
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City: Edmonton AB CA
This is worth a try to see how it works but the circuit current is going to take the path of lease resistance which will be your resistor and it MIGHT effect the performance of the speaker. With the lower current flow through the field coil the magnetic field will be reduced. You will have to decided if it works to your liking or not.
Gregb
Posts: 34
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Joined: May 2017
City: Huntington, WV.
It will definitely not be a permanent fix. I'm just dying to hear this thing. This is my fourth Philco restoration. You all know how it is. You just cant wait to hear it once it is complete. Ill post some pics once completed.
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Found a K-22 on ebay ($40). Should be here towards the end of next week. Fingers crossed that it doesn't need a re-cone.
Posts: 34
Threads: 6
Joined: May 2017
City: Huntington, WV.
While waiting on the new speaker, I put a 1.5k 10w resistor in parallel with the field coil (5.9k) of the speaker that came with the set. It did get all of my voltages where they needed to be. So I was pretty excited about that. I assume now that it is all out of alignment. So I grabbed Rider 7/7-78 to see if I could get her aligned. The IF was off a little. But I was able to get the 260 K.C to come in loud and clear using the procedure outlined. Its when I went to the next step where things didn't work. I connected my generator to the antenna post, set it to 1500 K.C, and the dial of the set to 150...nothing. For grins, I tried the 550 K.C, tuned to 55 on the set. Again, nothing. Could it be that far out?
I am using an old Heathkit SG-8. Those are usually a bit off. So I put my HP scope across it to be sure I'm right on the correct frequency. For grins I through my frequency counter on there. Its dialed it. Either I'm doing something wrong. Or it really is way out of wack!
Tom
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Connect an antenna and see if you can pull in any stations and don't worry just yet about dial calibration. If you do get something that will verify that the radio is somewhat working. If there is nothing then more work is needed.
Gregb
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City: Roslyn Pa
I would tune the generator around bit just in case osc is off frequency a good bit. If you don't get anywhere doing that would check the oscillator to see if it is oscillating. This can be achieved be listening for it in another receiver @ 260kc above the dial setting on victim. Or you can poke around the plate circuit of the 36 w/your scope to see osc activity. May need a low capacitance probe so doesn't load the circuit. Or use your counter to is if it's working and what frequency is working @.
If the osc isn't working it's time to revisit the osc coil. I think you said you rewound the tickler. Two important notes that will cause the osc to fail. If the wound in the opposite direction. Simple fix just flip the coil connection. The other is if there isn't enough turns. Best recollection is that it's abt 15 turns or so.
GL
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 03-09-2019, 08:59 PM by
Radioroslyn.)
Posts: 34
Threads: 6
Joined: May 2017
City: Huntington, WV.
So I tried the "quick & easy thing first. I reversed the wires going to the tickler coil. When I do that I don't even get any static. It goes completely quite. So I believe that I have it wound correctly. I did notice another oddity...I have static and squealing on the high end of the dial. When I get to about 670KHz, the set goes quite. From 670 to 540, there is absolutely nothing. Turn the dial back towards the high end, and the static comes back...there are no shorts on the tuning cap.
(This post was last modified: 03-14-2019, 09:47 AM by
tkibler.)
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