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[ OSD Control ]
H-Sync Signal V-Sync Si gnal CONTRAST BRIGHTNESS H / V POSITION H / V SIZE SPCC TRAPEZOID DEGAUSS PA RALLELOGRAM RECALL Exit 5V SCL / SDA H/V Sync Signal PWM Control Signal PC Jack Speaker Jack Degaussing Circuit Microphone E2PROM (IC402) H/V Sync Processor ( IC701 ) TDA4841 I2 C 12V I 2C DATA (SDA) I 2C 5V MICOM (IC401) 5V OSD IC (IC301) 80V I2 C R/G/B Contrast CLOCK(SCL) Input Signal R G B VIDEO Pre A mp (IC302)

12V

80V Heater ( 6.3V ) VIDEO Main A mp (IC303) G2 G1

H.V

DY

CDT

CUT OFF Circuit (IC304) R/G/B Bias 12V

Focus

I2 C

X-RAY Protection Circuit 15V Vertical Output ( IC601) TDA4866J

Vertical Blanking Brightness Control Circuit - 120V

12V
I2 C H/V Sync Signal

40V

15V

80V
Main Trans (T901)

FBT ( T701 ) H Deflection ( Q706) B+ 15V H-Linearity Circuit Auto Beam Limit Circuit

50V
D- Drive

Degaussing Coil
Voltage feedback Line Filter

15V 6.3V

Voltage feedback Main Power Control (IC901) DC/DC Converter B-Drive 50V

Input Voltage 100~240VA C (50/60Hz) Sub Power Control (IC902)

12V
Sub Trans (T902) Voltage feedback

D/D Feed Back

5.0V
Energy Saving Control Circuit Regulation Circuit

DESCRIPTION OF BLOCK DIAGRAM
1. SMPS(Switching Mode Power Supply) When you turn on the power switch, the operating procedure is as follows: 1) The AC line voltage is rectified by the bridge diodes D900 and C908 2) The control IC(IC901, IC902) starts switching and generates switching pulses in the primary turns of the SMPS transformer (T901, T902) 3) The switching pulses of the primary turns induce the secondary pulse of the transformer by the turn ratio. These pulses are rectified by each diode (D971, D961, D951 and D941, D922, D923) 4) Each rectified DC voltage (80V, 50V, 15V, 6.3V and 12V, 5V) is supplied to the main circuit. 2. Over Voltage Protection Circuit When the input voltage of IC901 Vin(pin 7) is more than Spec Voltage , all the secondary voltages of the SMPS transformer (T901) down to low value. 3. Display Power Management Circuit 1) OFF mode When no input of horizontal and vertical sync, Q903 is turned on and all the secondary voltages of the SMPS transformer (T901) down to low value. Then input power consumption is below 5 watts 4. X-ray Protection Circuit If the high voltage of the FBT reaches up to 29KV IN an abnormal case, Q807 operates and IC401 pin 41 came to low level, then IC401 control IC701 to stop Horizontal drive pulse and stop Horizontal deflection. 5. Microprocessor Control Circuit. 1) Horizontal and Vertical sync signals are supplied to the microprocessor (IC401). 2) Microprocessor(IC401) discriminates the operating mode from the sync. polarity and resolution. 3) After microprocessor reads these adjusted mode data stored at EEPROM, it controls operating mode data through IIC. 4) Users can control screen condition by the SELECT, BACKWARD, FORWARD and LEFT buttons. 6. D/D Convert Circuit. To obtain constant high voltage, this circuit supplies controlled DC voltage for FBT and Horizontal deflection circuit according to the horizontal sync frequency. 7. Horizontal and Vertical Sync Processor Circuit. The horizontal and vertical sync processor IC (IC701) has a sync detector, a saw-tooth generator, and drive function. So output horizontal and vertical drive signal control screen distortions. 8. Horizontal linearity Circuit. This circuit corrects the horizontal linearity for each horizontal sync frequency. 9. Horizontal drive and Output Circuit. This circuit is a horizontal deflection amplifier for raster scan. 10. ABL Circuit. This circuit limits the beam-current for the reliability of the CDT. 11. Vertical Output Circuit. This circuit takes the vertical ramp wave from the TDA4866(IC601) and performs the vertical deflection by supplying the saw-tooth wave current to the vertical deflection yoke. 12. Blanking and Brightness Control Circuit. Blanking circuit eliminates the retrace line by supplying a negative pulse wave to the G1 of the CDT. Brightness control circuit is used for control of the screen brightness by changing the DC level of the G1. 13. Video Processor Circuit. Video processor circuit consists of the video drive output block. The video drive IC(IC302) receives the video signal from PC. The gain of each channel is controlled by the voltage of contrast pin. The cut-off circuit compensate different voltage of each channel between the cathode and the G1 of the CDT. 14. OSD (On-Screen-Display) Circuit. This circuit displays on the screen information of the monitor's status. 15. SPEAKER Speakers are attached the monitor sides. DC Power voltage(12V) is supplied to Speakers. 16. MICROPHONE Microphone attached top of the monitor is connected to PC.

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