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Philco 89 Last Version Dies around 1200 kHz
#6

Well, here's an update.There is no short in th etuning cap; it plays with the plates fully meshed, stops oscillating as they disengage, but by ohming it there is no short anywhere. I pulled the OSC coil again, tried winding the cathode section various ways, but the problem persists. I then found that in fact with the bandswitch in the Police position, it would resume oscillating at the high end of the band, play stations up there, and if switching to the BC band again, it will receive some SW stations up there!! Also, sometimes on BC with plates fully meshed it stops oscillating, but can be restarted by a signal at that frequency from the signal generator. So the OSC tries to function but is unstable in function and frequency. I replaced the 700 pfd cap with a nice silver mica, and the resistor in the cathode circuit as well. I did not try the hair dryer trick yet. I think tonight I will pull it out again, and rewind the main section on the outer coil form and hope that is a cure.


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Re: Philco 89 Last Version Dies around 1200 kHz - by radiomikee - 09-10-2008, 08:27 AM



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