03-02-2016, 08:27 PM
Hello everyone
I am currently performing an electronic restoration of a Philco 39-25.
The radio powers on (everything seems normal but there is no reception. I have rechecked the wiring against the schematic which I traced out with a highlighter while comparing to the actual wiring. I thought it might be a oscillator coil problem but also rechecked for continuity which was also fine. Did the same with the broadcast and shortwave coils as well. I connected an outside antenna to see if that would help but there is no change. I also have touched the top of the caps on 6A8G, 78, and 75 to see if I could hear any hum . Nothing.
Any help will be appreciated
I have attached a link to the schematic
http://www.nostalgiaair.org/pagesbymodel...013286.pdf
I have listed the pin voltage readings that I got to help:
6A8-
PIN 1 = NO CONNECTION
PIN 2 = 6.67
PIN 3 = 114
PIN 4 = 12
PIN 6 = 12
PIN 7= 0
PIN 8 = 0
78-
PIN 1= 6.6
PIN 2= 189
PIN 3= 4.5
PIN 4= NEG 3
PIN 5= 0
PIN 6= 0
75
PIN 1 = 0
PIN 2 =211
PIN 3 = NEG 2.47
PIN 4 = 0
PIN 5 = 0
PIN 6 = 6.5
41
PIN 1 = 6.5
PIN 2 = 202
PIN 3 = 208
PIN 4 = NEG 13
PIN 5 = 0
PIN 6 = 0
84
PIN 1 = 6.5
PIN 2 = 292
PIN 3 = 292
PIN 4 = 300
PIN 5 = 0
ELECTROLYTIC (C17 ) = 191
ELECTROLYTIC (C18 ) = 208
ELECTROLYTIC (C41 ) = 302
I have noticed that I can get static when touching pin 4 of the 41 tube.
Kirk
I am currently performing an electronic restoration of a Philco 39-25.
The radio powers on (everything seems normal but there is no reception. I have rechecked the wiring against the schematic which I traced out with a highlighter while comparing to the actual wiring. I thought it might be a oscillator coil problem but also rechecked for continuity which was also fine. Did the same with the broadcast and shortwave coils as well. I connected an outside antenna to see if that would help but there is no change. I also have touched the top of the caps on 6A8G, 78, and 75 to see if I could hear any hum . Nothing.
Any help will be appreciated
I have attached a link to the schematic
http://www.nostalgiaair.org/pagesbymodel...013286.pdf
I have listed the pin voltage readings that I got to help:
6A8-
PIN 1 = NO CONNECTION
PIN 2 = 6.67
PIN 3 = 114
PIN 4 = 12
PIN 6 = 12
PIN 7= 0
PIN 8 = 0
78-
PIN 1= 6.6
PIN 2= 189
PIN 3= 4.5
PIN 4= NEG 3
PIN 5= 0
PIN 6= 0
75
PIN 1 = 0
PIN 2 =211
PIN 3 = NEG 2.47
PIN 4 = 0
PIN 5 = 0
PIN 6 = 6.5
41
PIN 1 = 6.5
PIN 2 = 202
PIN 3 = 208
PIN 4 = NEG 13
PIN 5 = 0
PIN 6 = 0
84
PIN 1 = 6.5
PIN 2 = 292
PIN 3 = 292
PIN 4 = 300
PIN 5 = 0
ELECTROLYTIC (C17 ) = 191
ELECTROLYTIC (C18 ) = 208
ELECTROLYTIC (C41 ) = 302
I have noticed that I can get static when touching pin 4 of the 41 tube.
Kirk