Philco 201X - Printable Version
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RE: Philco 201X - Radioroslyn - 05-19-2021
The 200 and 201 chassis were only used in the X cabinets. That's what makes it a 201X the combination of a given chassis and a particular style cabinet. For the most part X,H, and L are consoles. B's are cathedrals and tombstones. CS, LZ,LZX, and RX are chairsets. The list goes on...
Math is not my strong suit but here's a starting point. Perhaps one of the Mike's can help out will this issue. https://www.electronics-notes.com/articles/radio/rf-filters/what-is-constant-k-filter.php For now you could connect the top of the 100K resistor over the plate of the 75 to get it working.
RE: Philco 201X - 462ron - 05-20-2021
bgorman, here is a website that can help you calculate the inductance you need!
https://goodcalculators.com/resonant-frequency-calculator/
Ron
RE: Philco 201X - bgorman - 05-22-2021
>For now you could connect the top of the 100K resistor over the plate of the 75 to get it working<
Nice, I was thinking that I could do that very thing to at least be able to test it. Learning a little more everyday from you all.
Also thanks for the info on what the different letters mean.
RE: Philco 201X - bgorman - 05-22-2021
Ron
Thank you so much for the link, major time saver for me.
So in the calculator, for frequency, would I use the 10 KC it supposed to create ??
and the circuit has caps #69 & #72 as well as the #71 (adjustable). would I measure the total capacitance of all 3 ?
If so, the total capacitance measures out at 370 pf
If I plug in those 2 factors
10 Khz
370 pf
It gives me 684 Millihenries Does this seem right?
RE: Philco 201X - 462ron - 05-23-2021
I believe 69 & 72 are there to remove any residual IF carrier frequency left after demodulation. I would just use whatever value 71 is to solve for the inductance of 70.
Ron
RE: Philco 201X - bgorman - 05-31-2021
Life got busy here, but back at this unit. Hoping to get this figured out and be able to move on.
So the compensating cap #71 (as it is adjusted) measures 280 pf
The trap is 10KC
If I plug those 2 values into the calculator Ron links too, it gives almost 1H inductance. I'm no expert at this so wondering if that seems right ??
I found a 1H choke at antique electronics P-T158T but its only 40 ohms. If the calculation is correct would this one work ??
Thanks
Bob
RE: Philco 201X - 462ron - 05-31-2021
I come up with approx. .9 H. Not being an engineer, I would give it a try with the part you found and see how it goes, it won’t hurt anything! GL.
Ron
RE: Philco 201X - bgorman - 06-02-2021
< I come up with approx. .9 H. Not being an engineer, I would give it a try with the part you found and see how it goes, it won’t hurt anything! GL. >
Great thank you for chiming in Ron, feel more comfortable with trying it.
Bob