08-16-2009, 08:48 PM
Well, the coil wind went OK, reinstalled it and I have the same problems.
Mainly a squeal when tuned to the higher freqs. But it is not constant.
The set would pick up great say 1200, then tuning thru 1280, then higher it starts to squeal. Tuning back, the squeal does not stop. YOu have to fanagle with the tube caps, or touch the grid of the 2nd Det to 'reset' it.
I can take off the grid cap of the 36, and will stop. Volume down and cap reconnected, the set will receive ok on the high half of the band.
If I turn up the volume and tune higher than about 1200kc the set will squeal again.
I have canged the Osc cathode resistor to 8000 Ohms, but have tried other values. The only thing that changes it the squeal pitch. A 1300 Ohm squeals a lot lower.
Here is something I don't understand, when the grid cap is off the 36 tube, I can tune the lower end of the band. Otherwise the low end is not receivable. After about 750 kc the noise drops off, and I can't pick up a signal.
I am going to realign the IF tonight, but I think it is pretty much dead on at 260kc.
There is something that I am overlooking, but as far as I know, I"ve been over the set a few times, and all resistors within spec.
I dislike giving up an a set, but this one is giving me grief. Same situation os Chuck's Philco from He__*
http://www.philcorepairbench.com/tips/svctip42.htm
I only have one other #36 tube to swap, but it shows the same issues.
Perhaps making a little video would be in order.
I'd like to get this off to the owner, but I am afraid that I will not be able to get it working right.
Take care,
Gary.
Mainly a squeal when tuned to the higher freqs. But it is not constant.
The set would pick up great say 1200, then tuning thru 1280, then higher it starts to squeal. Tuning back, the squeal does not stop. YOu have to fanagle with the tube caps, or touch the grid of the 2nd Det to 'reset' it.
I can take off the grid cap of the 36, and will stop. Volume down and cap reconnected, the set will receive ok on the high half of the band.
If I turn up the volume and tune higher than about 1200kc the set will squeal again.
I have canged the Osc cathode resistor to 8000 Ohms, but have tried other values. The only thing that changes it the squeal pitch. A 1300 Ohm squeals a lot lower.
Here is something I don't understand, when the grid cap is off the 36 tube, I can tune the lower end of the band. Otherwise the low end is not receivable. After about 750 kc the noise drops off, and I can't pick up a signal.
I am going to realign the IF tonight, but I think it is pretty much dead on at 260kc.
There is something that I am overlooking, but as far as I know, I"ve been over the set a few times, and all resistors within spec.
I dislike giving up an a set, but this one is giving me grief. Same situation os Chuck's Philco from He__*
http://www.philcorepairbench.com/tips/svctip42.htm
I only have one other #36 tube to swap, but it shows the same issues.
Perhaps making a little video would be in order.
I'd like to get this off to the owner, but I am afraid that I will not be able to get it working right.
Take care,
Gary.
