Mitsubishi Electric 1786FD2 Service Manual page 50

MEA 1786FD2 CRT Monitor Service Guide
4. Dynamic focus CKT
According to the CRT spec
H dynamic focus Vpp = 350 V
4-1 Vertical dynamic focus
The signal from IC201 (pin 32) is a vertical frequency parabolic waveform.
Q321 : an inverting amplifier stage.
4-2 Horizontal dynamic focus:
The horizontal frequency parabolic waveform is amplified by T304.
5. Brightness & spot killer CKT.
5.1 G1 CKT
The bright control signal from UC controller is about 0 ~ 5V, when the voltage of bright control signal
increases, the current flow through R241 increases and the voltage of G1 decreases.
H dynamic focus Vpp = 150 V
Fig 4 Dynamic Focus circuit
Circuit Operation Theory
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