07-31-2019, 12:40 PM
I am finishing up the restoration of a Philco 42-360. I have replaced all of the paper caps and electrolytic caps, out of spec resistors and a couple of bad tubes.
I have aligned it and is working nicely... well most of the time. The oscillator tube is an XXL loctal tube and I have to wiggle it just so to get it to oscillate. I have cleaned and deoxed the contacts and socket and tried 3 different tubes. The result is the same. Once I wiggle the tube or remove and reinsert it it works fine until I turn off the radio off and let it cool and turn it back on.
That is one problem --- the other is with the volume control part 39 on the schematic. It is a 0.5 meg ohm pot. The volume increases as expected until it is about 3/4 clockwise. At that point the volume drops off. I have cleaned the the pot with deoxit. I am wondering if it is the pot or perhaps something wrong with the AVC circuit.
I tried replacing the pot with a 0.8 megohm pot that I had on hand. It did not work so well -- perhaps the taper was not correct.
Thanks in advance for any suggestions.
John w.
I have aligned it and is working nicely... well most of the time. The oscillator tube is an XXL loctal tube and I have to wiggle it just so to get it to oscillate. I have cleaned and deoxed the contacts and socket and tried 3 different tubes. The result is the same. Once I wiggle the tube or remove and reinsert it it works fine until I turn off the radio off and let it cool and turn it back on.
That is one problem --- the other is with the volume control part 39 on the schematic. It is a 0.5 meg ohm pot. The volume increases as expected until it is about 3/4 clockwise. At that point the volume drops off. I have cleaned the the pot with deoxit. I am wondering if it is the pot or perhaps something wrong with the AVC circuit.
I tried replacing the pot with a 0.8 megohm pot that I had on hand. It did not work so well -- perhaps the taper was not correct.
Thanks in advance for any suggestions.
John w.
