Philips FIMI Field Support Manual page 28

3.4.2 CRT CONTROL AND HEATER SUPPLIES
At secondary tap-off points voltages of varying values are rectified and
smoothed, each voltage level and its function is now described:
600V
This voltage is rectified by V57 and applied to a CRT control grid via pin 3;
also it is fed to potential divider network R75, R76 and R77 where the focus
potential is derived. The voltage level set by R76 is boosted by a voltage
waveform introduced from the horizontal deflection coil circuit via transformer
T53. The focus voltage is dynamic , peaking at a period immediately before and
after the horizontal sync pulse.
6V
This voltage is rectified by diode V58 and smoothed by C66, and provides the CRT
heater supply.
24V
Rectified by V59 and smoothed by C67 to provide the VCC supply for the IC
Lil.
64V
Rectified by V60 and smoothed by C68 to pro vi de the co 11 ector voltage for the
video amplifier, and in conjunction with -150V it establishes the potential for
the brightness control grid, this is input to the CRT on pin 2.
-150V
A voltage level rectified by V61 and smoothed by C69, used for brightness
control. Set by two potentiometers R72 - an external brightness control, and R73
which is preset.
3-6
FIMI MON 12"/15"
8305