Blue Voodoo 60: One power tube getting NO CURRENT!?!

[analog]

I am using a bias tester that measures current and plate voltage. One power tube is getting 450v on the plates and no current, the other tube is getting 515v on the plates and proper current. I opened it up and everything loops fine... has anyone had this problem? know a solution? I know a little bit about this stuff... trying to fix it asap

[vintagekiki]

This tube is probably defective. Some manufacturers in cathode incorporating some kind of "fuse". When the "fuse" burn (due to high currents) tube is permanently defective.
It happens to appear cold solder at the cathode (base pin 8)
Why are different plate voltage 450 vs 515V? Anode voltages should be fairly similar.
Are you sure that both measuring adapter (BMA2) are correct
When measuring tube replace each other their positions, to eliminate tube socket or measuring adapter.

[analog]

no. I have tried several different tubes and switched them from the different sockets. The v5 is getting no current, v6 is. I have done all the trouble shooting methods I can think of.

[vintagekiki]

Check connections from cathode V5 (base pin 8) and chassis.
If both tubes correct, but tube in position V5 no current, check for voltage on g2 (base pin 4). If no voltage check or replace
resistor in G2 (470 Ohm).
Check tube socket V5.

[analog]

I checked the power resistor and it reads fine @470 ohms. how do I check the voltage on the base pin? i assume I put the DMM on voltage and put the red on the pin and black to ground?

[vintagekiki]

I put the DMM on voltage and put the red on the pin and black to ground?

Exactly.
Black probe put to ground. With red probe DVM (DC range 1000V) check anode voltage (base pin 3), check g2 voltage (base pin 4). In both cases voltages is approximately 450 to 500V.
With red probe DVM (DC range 1000V) check cathode voltage (base pin 3). Voltage must be 0V (no voltage). If there is a voltage (can be at 500V) it is a sign to break the connection between the cathode and the chassis.

Be careful when measuring. Voltages greater than 50V are dangerous to life.