Acer AM501, Service Manual

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6.3 Horizontal deflection circuit
The horizontal deflection circuit is made up of HOR. synchronizer, HOR. oscillator, HOR. DRIVER, HOR.
OUTPUT and HIGHT VOLTAGE GENERATOR.
6.3.1 Horizontal synchronizer and oscillator
The horizontal sync. signal input to pin 1 of U401, to synchronize the horizontal oscillator, pin 5, 6, set
FH min oscillator frequency.
HOR. PHASE control by IIC.
6.3.2 Horizontal driver and output circuit
The driver waveform come out at pin 26 of U401, to the driver transistor (Q506), the driver transformer
(T501) supply the drive current, turn on and turn off the HOR. output transistor (Q801) alternately, a
saw-tooth current then be generated in the horizontal deflection coil.
P801, it supply a positive or negative current to move the raster to left or right side.
6.3.3 High voltage generator
(1) Anode voltage
The high voltage applied to CRT anode is obtained by boosting and rectifying the pulse voltage
generated during the horizontal fly-back period with fly-back transformer (F.B.T.)
(3) Screen voltage
The screen voltage is obtained by dividing the anode voltage with screen VR.