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Philco 84 Restore
markmokris
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Posts: 109
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City: Ann Arbor, Michigan
#1

07-31-2015, 11:09 AM
I am just finishing up a restore of a Philco 84 cathedral.  I had to rewind the primaries on the antenna and oscillator coils.  I replaced all the capacitors. I also replaced all the dogbone resistors. I have adjusted the regeneration control, and peaked the IF capacitors.  It is playing with pretty good volume with only an 8 ft. piece of antenna wire.

I need to still make the 2 meg ohm resistor change from the service tip in the IF transformer to see if it plays even better.

Question...I noticed that someone had removed the "gimmick" capacitor (#3) so I replaced it.  It seemed to make no difference.  What exactly is the capacitor doing?  Coupling a little extra signal from the antenna to the oscillator?

Why would it seem to not be needed?

   

Thanks,

Mark K8KZ
(This post was last modified: 07-31-2015, 11:09 AM by markmokris.)
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GarySP
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City: Westland, MI
#2

08-01-2015, 08:46 PM
Hi Mark.  I have that same gimmick cap in my 41-280.  My guess is it works as a filter.  I don't know exactly how, but others on this site can offer more info than I can.  All I know is that I was told to keep it in the circuit or you can pick up a lot of "white" noise.  Take care, Gary
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
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