05-08-2020, 09:18 PM
Hello,
Is part number 36-1533 required on this radio? If not, do I need to put a jumper in it's place?
Is part number 36-1533 required on this radio? If not, do I need to put a jumper in it's place?
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philco model pt-4
05-09-2020, 03:41 AM
Hi and welcome,
Can't leave the circuit open. If you your use a jumper in it's place you'll have a lot of hum. Replace it with a 500 ohm 2w resistor and increase the value 30-2382 to 47mfd@160vdc. This will satisfy the electrical needs but may not provide any magnetism which the speaker requires. 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
05-09-2020, 08:43 AM
Thank you for responding. What exactly is part 36-1533?
05-09-2020, 09:21 AM
Look at the service info for the PT-4:
https://philcoradio.com/library/download...20Book.pdf 36-1533 is the field coil of the electrodynamic speaker (this is before the days where they could cost effectively make strong permanent magnets). The field coil doubled as part of the original filtering design.
05-09-2020, 10:04 AM
A couple of thoughts. If your field coil is open you can do as I mentioned. The pole inside the spkr as some residual magnetism and it may work. How well it will work I'm not sure. I have heard of sticking a small rare earth (powerful) behind the fc at the back of the spkr to increase the magnetism.
The other option is the replace the spkr with a permanent magnet one. I think that this set uses a 4"x6" oval. These are not all at common. And the other trick is to be able to mount the output transformer on it's back. I'm not saying it's impossible but will take a little hunting to find a proper candidate. 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
05-09-2020, 10:30 AM
Terry,
Is 36-1533 an existing part of the speaker? If so, where is it located?
05-09-2020, 10:37 AM
Yes. If you were to grab and rip it from the chassis you would have 4 wires hanging. 2 of them go to the transformer that is mounted on the top of the spkr. the other 2 are corrected to the field coil pn 36-1533. Don't rip the spkr out!
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
05-09-2020, 10:47 AM
Terry,
Thank you for your input. Once I got my head out of my butt I found then leads & their connections....thanks again. Gene
05-09-2020, 10:54 AM
Here's an explode view of a generic eletrodynamic speaker.
https://www.quora.com/Can-I-use-an-elect...n-speakers 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
05-09-2020, 11:08 AM
If you measure the resistance from pin 4 of the 50L6 to pin 7 of the 35Z3 you should see 500 ohms or so. If it's way higher your fc is suspect. Just for grins measure the resistance from pin 3 of the 50L6 to pin 4 of the 50L6. Should see several hundred ohms.
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
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