07-23-2011, 02:01 PM
Pin 4 on the 1T4 is being used as a tie point, there is no element of the tube connected to it. Pin 4 of the 3Q5 is connected to the B+ supply and a convenient tie point for one end of the 1 meg resistor. From pin 4 of the 1T4 the schematic I have shows a connection to the pin 2 of the 1U5 which is it's plate. If your set has an additional 1 meg resistor andit looks like the original , then follow what is in your set. Production changes and substitutions were not always documented, and has been stated, this particular change would probably not matter all that much.