Philco Model 70 volume and reception problems - Printable Version
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Philco Model 70 volume and reception problems - radionut - 11-28-2010
My radio lose its volume after being played for a while .athen the volume comes back up.Also During reception ,the radio blanks out and has anoise level that is not affected by the volume control .It is a sort of hissing staticky sound.After i turn off the radioand it cools down , it plays fine for a while after turning it on, then it does the low volume and no reception thing again.I will appreciate any help I can get. Claude
Re: Philco Model 70 volume and reception problems - Ron Ramirez - 11-28-2010
Take a good look at your 24 and 27 tubes, especially if they are the old globe shaped tubes. Watch them while the set is in operation, preferably with the chassis and speaker out of the cabinet and in a room with the lights dimmed.
Watch and see if any of the tube filaments flicker or go out in one of the 24 or 27 tubes. If so, that's your culprit.
I've seen this happen before in the older Philco sets. If you find one with an intermittent filament, you could try pulling the tube and reflowing the solder in the filament pins, but more likely than not, it is a defect in the filament structure. I've seen these tubes with filaments that would flicker pretty badly.
The newer (ST, taper-top or shouldered type) 24 and 27 tubes do not seem to have this problem.
Re: Philco Model 70 volume and reception problems - radionut - 11-29-2010
Ron: Thanks very much for the info about the tube filaments. I replaced one of the tubes and it seems to have corrected the problem. Thanks again for your help. Claude
Re: Philco Model 70 volume and reception problems - Radioroslyn - 11-29-2010
Hey Ron
Tnx for the tip. My old 370 has been doing the same thing. When I first got it working the 227 oscillator tube filament would die out and I would lose reception. Replaced the 227 and it worked fine for 6 or 8 months but now the volume goes up and down all by it's self. Haven't looked into it yet but will give the filaments a hairy eyeball.
Terry