11-07-2011, 03:15 PM
Hi,
Restoring a Philco 38-12. If the 6A7 tube isn't functioning would that be a cause for the dial lamp not to turn on? I'm getting static but no reception of signal. I have replaced all caps. I noticed that the 78, 75, 41 and 84 tubes lightup, but the 6A7 does not and the grid cap is extremely loose. I tested the tubes on a Precision 612 tube tester and the 6A7 tested to replace. Voltage readings are as follows:
Tube 41:
S= 194vdc
G= -10vdc
P= 176vdc
Tube 84
K=249vdc
Tube 75
P=83vdc
D1= -2.4vdc
D2= -2.4vdc
K= -2vdc
Tube 78
P= 189vdc
S= 100vdc
Tube 6A7
Osc P=186vdc
Osc G= 0
S=99vdc
P=189vdc
+ side 12uf (I used 20uf) to - electrolytic = 254vdc
+ side of 4uf(I used 8uf) to chassis ground=196vdc
Voltage reading were taken with 113vac input
Thanks,
Mike
http://www.nostalgiaair.org/Resources/236/M0013236.htm
Restoring a Philco 38-12. If the 6A7 tube isn't functioning would that be a cause for the dial lamp not to turn on? I'm getting static but no reception of signal. I have replaced all caps. I noticed that the 78, 75, 41 and 84 tubes lightup, but the 6A7 does not and the grid cap is extremely loose. I tested the tubes on a Precision 612 tube tester and the 6A7 tested to replace. Voltage readings are as follows:
Tube 41:
S= 194vdc
G= -10vdc
P= 176vdc
Tube 84
K=249vdc
Tube 75
P=83vdc
D1= -2.4vdc
D2= -2.4vdc
K= -2vdc
Tube 78
P= 189vdc
S= 100vdc
Tube 6A7
Osc P=186vdc
Osc G= 0
S=99vdc
P=189vdc
+ side 12uf (I used 20uf) to - electrolytic = 254vdc
+ side of 4uf(I used 8uf) to chassis ground=196vdc
Voltage reading were taken with 113vac input
Thanks,
Mike
http://www.nostalgiaair.org/Resources/236/M0013236.htm
