02-02-2009, 06:56 PM
I have a Philco 81 that I repaired last year. I recapped it and replaced the dogbones with new resistors. I changed the 4 meg resistor on the 2nd detector grid to a 2 meg resistor. I put in all NOS tubes. I also did an alignment. I rebuilt the bakelite blocks so they are still in the chassis as original. Basically, I did a full overhaul under the chassis trying to keep it as original as possible. The radio played very nicely and all the voltages were good. But that was last year.
I didn't use the radio for several months, so when I tried to use it recently it was dead. The audio section is ok, when I touch the grid cap of the 2nd detector, I get hum. I can touch the 1st detector grid cap and nothing happens. But when I remove the grid cap from the 1st detector the set starts to make noise and pick up stations. When I replace the grid cap the set plays normally. I suspect that the oscillator is failing to start, but something about removing the grid cap gets it going. I swapped the 1st detector and 2nd detector tubes and it made no difference. I haven't pulled the chassis out, but I am ready to now.
Where would you suggest I begin to determine if my problem is in the oscillator or in the RF front end? Are there any other suggestions? If the regeneration is not set right, could it cause this problem?
I have restored several Philcos and they work nicely when you get them repaired right.
This is a nice, original condition set and I would like to have it play well. And yes, I like Philcos.
I didn't use the radio for several months, so when I tried to use it recently it was dead. The audio section is ok, when I touch the grid cap of the 2nd detector, I get hum. I can touch the 1st detector grid cap and nothing happens. But when I remove the grid cap from the 1st detector the set starts to make noise and pick up stations. When I replace the grid cap the set plays normally. I suspect that the oscillator is failing to start, but something about removing the grid cap gets it going. I swapped the 1st detector and 2nd detector tubes and it made no difference. I haven't pulled the chassis out, but I am ready to now.
Where would you suggest I begin to determine if my problem is in the oscillator or in the RF front end? Are there any other suggestions? If the regeneration is not set right, could it cause this problem?
I have restored several Philcos and they work nicely when you get them repaired right.
This is a nice, original condition set and I would like to have it play well. And yes, I like Philcos.
