07-27-2009, 02:23 PM
All coils check out OK. All resistors are now within 20%, and most within 15%. I had to change out quite a few. The 6A7 is NOS and checks very high. B+ is on the money at 257 volts (at 110 volts in). The screen voltage on the 6A7 and 78 is a little low at 67 volts. But it's hard to say what it should be with all the changes. I did not disturb or check capacitor 13 (110pf mica).
The set is NOT OSCILLATING on the Police band. The oscillator grid is positive and I cannot pick up anything on my Realistic DX440. When the oscillator feedback coil (which was of course open) was rewound, I used about 15 turns. I am not exactly sure how many turns were on the original, since it was in many pieces (green disease). But I assumed it was not critical (that was the case with several other Philcos I have restored and had to rewind this coil). In any case, I pulled the coil out and rewound the feedback coil with 22 turns (#38 cotton covered wire). Still no oscillation, although I get squeals and what sounds like parasitic oscillation at the high end of the band.
Is it possible I should have used FEWER TURNS on the oscillator coil feedback winding? There was no change in performance on the broadcast band.
Has anyone restored one of these recently and remember exactly how many turns were used?
I used scotch tape to replace the original plastic insulator on which the coil was wound.
The winding was positioned approximately where it was originally, on the cold end of the coil. And the winding direction much be correct, else the broadcast band would not work.
THANK!!!
The set is NOT OSCILLATING on the Police band. The oscillator grid is positive and I cannot pick up anything on my Realistic DX440. When the oscillator feedback coil (which was of course open) was rewound, I used about 15 turns. I am not exactly sure how many turns were on the original, since it was in many pieces (green disease). But I assumed it was not critical (that was the case with several other Philcos I have restored and had to rewind this coil). In any case, I pulled the coil out and rewound the feedback coil with 22 turns (#38 cotton covered wire). Still no oscillation, although I get squeals and what sounds like parasitic oscillation at the high end of the band.
Is it possible I should have used FEWER TURNS on the oscillator coil feedback winding? There was no change in performance on the broadcast band.
Has anyone restored one of these recently and remember exactly how many turns were used?
I used scotch tape to replace the original plastic insulator on which the coil was wound.
The winding was positioned approximately where it was originally, on the cold end of the coil. And the winding direction much be correct, else the broadcast band would not work.
THANK!!!
