
Me
Member
Hello again. I'm sat here now with a function generator, multimeter, oscilloscope and what-not. I've re-measured now I know what the pins do, and measured relative to the valve cathodes using a DC multimeter. Should make more sense now...
All preamp heaters are at 6.84V roughly.
V1
Half A:
Anode to cathode: 178.2V
Grid to cathode: -1.381V
Half B:
Anode to cathode: 178.5V
Grid to cathode: -1.239V
V2:
Didn't bother as it doesn't work on any channel and this is for Ch3 only right?
V3
Half A:
Anode to cathode: 399V
Grid to cathode: -5.93V
Half B:
Anode to cathode: 10.56V
Grid to cathode: +0.9V
V4
Half A:
Anode to cathode: 222V
Grid to cathode: -1.625V
Half B:
Anode to cathode: 193V
Grid to cathode: -1.253V
V5
Half A:
Anode to cathode: 205.4V
Grid to cathode: -1.183V
Half B:
Anode to cathode: 199.3V
Grid to cathode: -1.146V
V6
Half A:
Anode to cathode: 168.5V
Grid to cathode: -2.471V
Half B:
Anode to cathode: 157.6V
Grid to cathode: -2.435V
Is the grid in the 2nd half of V3 supposed to be +ve relative to the cathode???
I'll try to follow the signal next with an oscilloscope but it's tricky to get a cathode ground reference using the little croc clip on the oscilloscope. If you don't hear from me again I'm probably dead!

All preamp heaters are at 6.84V roughly.
V1
Half A:
Anode to cathode: 178.2V
Grid to cathode: -1.381V
Half B:
Anode to cathode: 178.5V
Grid to cathode: -1.239V
V2:
Didn't bother as it doesn't work on any channel and this is for Ch3 only right?
V3
Half A:
Anode to cathode: 399V
Grid to cathode: -5.93V
Half B:
Anode to cathode: 10.56V
Grid to cathode: +0.9V
V4
Half A:
Anode to cathode: 222V
Grid to cathode: -1.625V
Half B:
Anode to cathode: 193V
Grid to cathode: -1.253V
V5
Half A:
Anode to cathode: 205.4V
Grid to cathode: -1.183V
Half B:
Anode to cathode: 199.3V
Grid to cathode: -1.146V
V6
Half A:
Anode to cathode: 168.5V
Grid to cathode: -2.471V
Half B:
Anode to cathode: 157.6V
Grid to cathode: -2.435V
Is the grid in the 2nd half of V3 supposed to be +ve relative to the cathode???

I'll try to follow the signal next with an oscilloscope but it's tricky to get a cathode ground reference using the little croc clip on the oscilloscope. If you don't hear from me again I'm probably dead!

