Tube Biasing - Samsung CC9511 Service Manual

6.4. REGULATORS
Four voltages are used to run the video amplifier
and sync processing circuit. The 150 volts is used by
the back ground to set black level. The 65 volts is
used by the video power output amplifier. The 25
volts is reduced to 12 volts by the 7812 regulator for
use by the LM12010 The 8 volts lights the filament
through a resistor and powers all of the digital logic
through a 7805 regulator.
7. TUBE BIASING
7.1. PROTECTION
All elements of the tube have arc protection. The
arc current should be returned through the arc
ground, not the signal ground, back to the tube in a
short direct low impedance path.
7.2. BYPASSING
Grid bypassing is referenced back to the 65 volt
supply. Then the 65 volts is bypassed to ground.
This wires all biasing grids in common mode for
maximum ripple rejection of the high current 65 volt
supply.
7.3. HEATER
The heater is powered from 8 volts dropped by a
power resistor.
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