[ High Voltage Processing Circuit ]; [ Abl Circuit ]; [ Dynamic Focus Circuit ] - Mitsubishi Electric Diamond View 1995SL Service Manual

1995SL CRT Monitor Service Guide
Chapter 2 Circuit Operation Theory

[ High Voltage Processing Circuit ]

The high voltage circuit uses two MOSFETs (Q320 and Q323) to drive FBT to generate HV up to 26KV. HVDRV
and BDRV both are from IC201 but are opposite waveforms. HV-FB is the feedback signal for HV compensation
to adjust the duties of HVDRV and BDRV.

[ ABL Circuit ]

When the loading of video increases, the current through R383 increases. And the base voltage of Q382
decreases. So the voltage of ABL to the video board decreases to keep the light output from going up.

[ Dynamic Focus Circuit ]

The monitor uses double focus CRT and it needs vertical and horizontal parabolic focus signals to input to CRT
G3 and G5 grids.
The vertical parabolic signal from IC201 pin32 is amplified by Q324 to obtain about 150Vpp at the collector of
Q324.
The horizontal parabolic signal is taken from Cs capacitors and amplified by T304 to reach about 350Vpp signal
at pin1 of T401 to combine with vertical parabolic signal and get into FBT focus pack.
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