Cathode cap and resistor - Printable Version

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+--- Thread: Cathode cap and resistor (/showthread.php?tid=22671)

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Cathode cap and resistor - Patrick - 07-23-2021

Someone gave me a chassis, which I believe to be from a 37-610. Looks the same (5 tube, of which all were missing), and dial is correct. Thought I'd clean it up and re-cap it, etc.

Removed the RF chassis to get to the buried caps. There is a .05 cap and a parallel 100Ω resistor from pin 8 (cathode) of the 6A8 det.osc. to ground.

It doesn't show up in any schematic, and no reference is made in any service bulletins that I can find. Don't know if there are any other oddities. Any ideas?

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RE: Cathode cap and resistor - Patrick - 07-24-2021

Found it!! Further research showed that there was 4 different variations of this chassis: Code 121, 122, 125, and 126. Codes 121 and 122 did not have the resistor/capacitor, but 125 and 126 did. 121 and 125 had the rectifier on the top of the transformer, and 122 and 126 did not.

Anyone else come up with the same or different solutions?

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RE: Cathode cap and resistor - Ron Ramirez - 07-24-2021

What you want is Service Bulletin 249B, which is in the Philco Library.

This Service Bulletin covers the 37-610 Codes 125 & 126.

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RE: Cathode cap and resistor - Patrick - 07-24-2021

Thanks Ron. That's where I found it!

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