Acer AF705, Service Manual

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3. INTRODUCTION:
C708 is a 17” multisync color monitor. The horizontal frequency range is from 30khz to
70khz, and the refresh rate is from 50hz to 160hz. The circuit includes four major parts, the
power supply circuit, the deflection circuit, the video circuit and the digital control circuit. is
the function block diagram.
A. POWER SUPPLY
Transfer AC source to DC source that supply all the circuit power. It includes:
(1) +13.5V: For horizontal and vertical deflection circuit.
(2) –11.5V: For vertical deflection circuit.
(3) +7.2V: For CRT heater, parts of video pre-amp circuit.
(4) +53V: For B
+
Boost circuit.
(5) +80V: For video circuit
(6) 9.2V: for MIRCO- P
Fig 2 is the function block diagram of power CKT.
B. DEFLECTION:
Produce YOKE deflection current of horizontal and vertical, CRT H.V and bias that makes
screen raster.
C. VIDEO:
amplify the video signal and add the signal to the cathode of CRT to produce video on the
screen.
D. DIGITAL CONTROLLOR:
With the EEPROM and PROGRAM, the micro-processor (u-P) control all the picture
performance.
From the key control, the user can change the H-size, V-size, V-center, H-phase.