[crestavega]

I have replaced capacitors on me T128 and now getting sensible kathode kurrent on all tubes. however I still don't seem to have any serious work being done by the PA.
I have discovered that the "Final Drive" voltage seems to sit at -70V. Im not sure this is right
I discovered this on the built in test meter, which in position 5 (Final Drive) pegged hard over left in standby. no change on Tx.
The manual states that in this position, the test meter will show deflection when the grid voltage of one of the tubes becomes positive wrt Earth.
I think the grid is supposed to sit at slightly negative potential in order to stop excess anode current? yet sitting at -70V seems like it will choke the valve from doing anything...?
I must confess I am a bit stumped as to where that -70V is coming from.
One thing I did notice is that from cold, this voltage is 0V but seems to creep down to -70V as the filaments heat up.
cheers
Tris