08-08-2015, 01:30 AM
Well, checking things again tonight, I at least figured out why pin 6 and 7 on the 7AF7 were out of range. I misread the schematic and put a 68 ohm resistor in in place of a 6800 ohm on pin 7. SO, fixed that and now the voltage readings look better there.
I did notice a spark once at the terminal point where the .1 uF 7AF7 Plate Decoupler cap and the 470K ohm Phono Amp Plate Decoupling Resistor are joined. It looked to me like an unacceptable solder joint so I reflowed it and I have not noticed any spark since.
The voltage on pin 3 of the 7X7 is still slightly over -1 v DC and there is still a visible glow in the tube. I checked voltages on the 2 6V6's as well and they all read normal other than -13 v dc on each pin 5 (calls for -1.8 and -1.7).
I can still pick up a local station @ 1600 but no others.
Finding 2 mistakes now, I am less confident of my work, and have learned not to shotgun replace everything at once. Hopefully I can learn more troubleshooting from this as well.
I did notice a spark once at the terminal point where the .1 uF 7AF7 Plate Decoupler cap and the 470K ohm Phono Amp Plate Decoupling Resistor are joined. It looked to me like an unacceptable solder joint so I reflowed it and I have not noticed any spark since.
The voltage on pin 3 of the 7X7 is still slightly over -1 v DC and there is still a visible glow in the tube. I checked voltages on the 2 6V6's as well and they all read normal other than -13 v dc on each pin 5 (calls for -1.8 and -1.7).
I can still pick up a local station @ 1600 but no others.
Finding 2 mistakes now, I am less confident of my work, and have learned not to shotgun replace everything at once. Hopefully I can learn more troubleshooting from this as well.
