View Single Post
  #25  
Old 09-27-2009, 03:23 PM
rollei35guy rollei35guy is offline
...
 
Join Date: May 2008
Posts: 86
Sorry to hear that. How did it go out? Was it operating for a wile? Is that cap still getting hot?

Quote:
Originally Posted by radio nut View Post
The one thing I would really like to ask someone from Philco is why was this set not a "clean "series string as far as heaters went.Why all the side taps into B+ lines and junctions to IF secondaries?I was thinking that my overvolting issue was from a leaky cap tapped into a B+ line.I guess I will find out soon(not soon enough)!
I was puzzled by the complexity of the heater string too until I realized it's a directly heated cathode. In other words the heater and the cathode is the same element. So you have both the heater and signal on the same element.

You might well be right about the caps shorting out either from cleaner or age. It's possible that they are good initially when you turn on the set but break down after being at working voltage.

If you can figure out what the filament resistance should be on the 1lb4, you could wire in a resistor of similar value as a dummy filament so you could trace out the problem with out burning out another 1lb4. On the other hand you might burn out something else.
Reply With Quote
Audiokarma