Philco 90-Extra Capacitor - Printable Version

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+--- Thread: Philco 90-Extra Capacitor (/showthread.php?tid=3529)

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Philco 90-Extra Capacitor - cwysong - 07-31-2011

I've got a Philco 90 chassis with a single 47 tube. There is a bakelite cap connected to part 55, which is the choke. The part is a 4989-J, which is a .09 cap. Both wires of the choke go to this bakelite cap, and one line goes to one electrolytic and the other goes to the second electrolytic.
I replaced the electrolytics and powered it up, and it plays just fine.

It's clear that this is a Philco part, and it looks like it is original to the chassis. Has anyone seen this before? I don't see it on the schematic nor on the under chassis layout.

Thanks,
Chris

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Re: Philco 90-Extra Capacitor - exray - 08-01-2011

From your description your choke is set up as a 120-cycle trap using the capacitor to create a resonant circuit.

Two choices here. Leave it out if there's no hum, or replace it. I wouldn't leave the old one in place.

Although its not your chassis you can see an example of the usage on Page 13 of the Rider info on the Model 90

http://www.nostalgiaair.org/PagesByModel/881/M0013881.pdf

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Re: Philco 90-Extra Capacitor - cwysong - 08-01-2011

Thanks for the information. What I have is exactly what is on page 13. I'm going to replace the cap and leave it in.

I appreciate your help!

Chris

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