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Philco 41-221 Oscillator Adjustment? - Printable Version

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Philco 41-221 Oscillator Adjustment? - NV3G - 05-22-2013

I am helping a friend with his Philco 41-221. It has been recapped by a previous repairman. The radio frequency on the dial is way off. Where is the adjustment for changing the oscillator frequency so that it agrees with the dial pointer.

Also, at the very high end of the dial there is oscillation or motorgboating. The electrolytic capacitors and paper capacitors have been changed.



Thank you for your suggestions.
Oscar
nv3g

RE: Philco 41-221 Oscillator Adjustment? - Mondial - 05-22-2013

The loctal tubes are notorious for developing dark oxide corrosion on the pins, resulting in intermittent contact with the socket. It is usually very hard to remove.

I have had the best luck with thin strips of 400 grit wet or dry sandpaper. Loop the strip around each pin and pull it back and forth until the pin is shiny and clean. To prevent future corrosion, apply a thin coating of silicone dielectric compound to each pin. The silicone is available in small tubes at auto parts stores and is used for waterproofing electrical connectors and spark plug terminals.

RE: Philco 41-221 Oscillator Adjustment? - codefox1 - 05-22-2013

Agree with all.

You can also beg an old currette or two from your dentist or hyguenist. Still will be plenty good enough to scrape loctal pins and the tools also "goes around corners" to get the inside edges. If the sockets are nasty too, deoxit and plunger like stabs with a thin toothpick usually helps a lot. Remember to bend toward the nipple on the base of loctals to remove them from sockets without harm.

RE: Philco 41-221 Oscillator Adjustment? - Ron Ramirez - 06-03-2013

Oscar, if you can get a copy of the Philco service information for this set, it shows where the trimmer for the LF oscillator is located (on back of the chassis).

Nostalgia Air is currently down, but you can also find it here:

http://audiophool.com/Misc/philco_41-221.djvu

(requires IrfanView or other compatible DjVu file viewer)

RE: Philco 41-221 Oscillator Adjustment? - codefox1 - 06-05-2013

N.A. back up for the moment anyway.

Schematic here as alternative:

http://www.nostalgiaair.org/PagesByModel/394/M0013394.pdf