B&K 667 issue
 

Anyone have the schematic, or at least the tube socket wiring diagram for one of these?

Someone replaced Socket 6 in this one and of course when I stick a 12AU7 in there, it only lights half of it at twice the brightness. Yikes.

So in essence, I am sure it is wired wrong. but does someone have the proper schematic or wiring diagram?

Thanks.

12au7 heater is 12 volts so it shouldn't be to difficult to figure out the heater connections. Lookup the tube where the heater connections are then check how much voltage the tester is putting out. Seems like only one side of the tube heater is working, make sure both sides of the tube is wired for the 12 volts.

Most tube checkers check the 12AU7 at 12 volts. It could be that the wiring going to pins 4 or 5 and 9 is reversed.
I'm not too familiar with the 667, as I have the 707 and a 747.
Look on the internet. There's information on the 707 but not sure about other models.