User`s manual

4.3.4 0B2 Gas Discharge Tube
The 0B2 is a cold-cathode, glow discharge tube. In combination with a 10K Ohm
resistor it provides a regulated 108 Volts to the 6BC8 gain reduction stage. It will glow
orange or purple depending on the variety. This tube can fail two ways; it stops glowing
and the gain reduction meter rises to +3, or the light dances in the tube causing a rumble
or squeal in the audio signal. With normal gain reduction this tube will dim slightly.
This is normal.
4.3.5 Bleeder Resistor
There is a 270K Ohm bleeder resistor across the first power supply capacitor. In the
event of a choke failure, the input filtering capacitor will discharge. Under normal
conditions the power supply will not carry residual voltage seconds after power is
interrupted. Always check the power supply capacitors for stored voltage when
performing repairs.