02-08-2021, 10:39 PM
Hi all. I'm still very new here and hope this is posted correctly.
My Philco PT-25 has been playing well since I replaced capacitors. I turned it on earlier today and just as the audio was coming up as the tubes warmed up the pilot lamp got really bright and went out. I could hear a little drop and then return to the volume level as this happened. The set still plays just fine but I thought I remembered reading somewhere to try to keep the pilot lamp operational to help tube lifetimes.
This evening I replaced the lamp and turned the radio on and the same thing happened. The lamp has always been brightest when the power is first switched on, then dims until the tubes warm enough to start playing, and then maintained a fair brightness. I think it's odd that the lamp behaves normally until the sound starts becoming audible.
What should I do next to figure this out?
The schematic (Part 11 1940 RMS Year Book) shows the pilot lamp directly in the power and filament circuit with what I believe is the metal cased resistor pair mounted to the chassis. The resistances in this were ok when I replaced the caps.
I may not be able to get back to working on it for a couple of days. My furnace is getting worked on tomorrow... whole other problem.
Thanks in advance.
-Dave
My Philco PT-25 has been playing well since I replaced capacitors. I turned it on earlier today and just as the audio was coming up as the tubes warmed up the pilot lamp got really bright and went out. I could hear a little drop and then return to the volume level as this happened. The set still plays just fine but I thought I remembered reading somewhere to try to keep the pilot lamp operational to help tube lifetimes.
This evening I replaced the lamp and turned the radio on and the same thing happened. The lamp has always been brightest when the power is first switched on, then dims until the tubes warm enough to start playing, and then maintained a fair brightness. I think it's odd that the lamp behaves normally until the sound starts becoming audible.
What should I do next to figure this out?
The schematic (Part 11 1940 RMS Year Book) shows the pilot lamp directly in the power and filament circuit with what I believe is the metal cased resistor pair mounted to the chassis. The resistances in this were ok when I replaced the caps.
I may not be able to get back to working on it for a couple of days. My furnace is getting worked on tomorrow... whole other problem.
Thanks in advance.
-Dave
