Somehow this discussion got off on measuring plate current, which makes no sense since there is already a means of checking cathode current using the two cathode resistors. In any case, my issue was definitely the shunt resistor, which had elevated to 9 ohms but physically looked OK! Replaced with three parallel 10 ohm 1/2 watt resistors and now get good cathode current readings.
The two cathode resistors in my unit had been changed to 10 ohm 2W and they measure very close to that and equal. Unfortunately, my brand-new tubes are not balanced, one has? .2 volts and the other .35 volts across their respective resistors or 20ma ans 35ma. I am going to check my stock for more 6JB6's and hopefully I can find a better match. How much of a difference is a problem? Also checked the screen resistors and they are closely matched so I don't think anyhing other than the tubes themselves would be causing the unbalance.
One problem I see is considerable power drop off on the higher bands. How much CW output should a good T4XC produce? I get 110W on 80 meters but down to about 60W or less on 40 and less even less on higher bands. I suspect the 12BY7 driver and I am going to look for one of them in my stock also. I have a 12.6mhz crystal but it apparently is not working as I get no drive on 160. Another thing to check.
Once I am confident that it is not a tube issue, I will do a complete alignment. I have a question about the RF and Mixer stage alignment procedure in section 5-8 of the manual. Item c-5 and c-6 refer to detuning by putting a screwdriver on the rotor. This seems like a weird way to do things. Has anyone come up with a better approach. Also, item c-5 says to tune the front injection trimmer, while item c-6 says to tune the rear injection trimmers - note plural. There are 4 trimmers, does that mean to tune the 3 rear trimmers? Perhaps someone has a better way of doing this?
Doug, WA3DSP
Doug Crompton WA3DSP