Video Circuit & Osd; Micro Controller System; Vertical Deflection - Mitsubishi Electric DPro930SB-BK Service Manual

2. Video Circuit & OSD
The video amplifier system is consist of the Pre-Amplifier, the Video-Power-Amplifier, and the cutoff-Voltage
circuit.
a) The U201 (LM1267) is a three channel video pre-amplifier IC, that controlled by MCU IIC bus for the
features of contrast, output DC level, 3 SUB gain controls (R-Gain, G-Gain, B-Gain).
b) U201 PIN 23 need a positive pulse for clamping and PIN 24 also need a positive pulse for blanking.
c) The OSD mixer processes are on pin 1, 2, 3, and the OSD -SEL on pin 4.
d) The Video-Power-Amplifier U204 (LM2463) is a three channel hybrid IC which functions as a cascade
type transistor amplifier to reach the high bandwidth performance.
e) The Cutoff- Adjusting circuit is consist of U203 to provide the function of background white-balance.
f) The U202 (MTV030N-46) is a OSD generator outputs the R. G. B. and FBLK signals that MCU shows the
monitor's status and the user adjusting indications. This IC is synchronized by horizontal and vertical sync
input on pin 5 and pin 14.

3. Micro Controller System

a) The MCU U701 (MTV212) provides the following functions:
1) Output 4 PWM to adjust the voltage controlled functions such as CG-H, CG-V, ROTATION, H-LIN.
2) When MCU detected the power saving signal, two outputs pin 28 and pin 29 will change the Hi/Lo state
to control the power saving circuit.
3) There still has 5 CS outputs used to control the S-correction capacitor for horizontal deflection stage.
4) MCU have 3 A/D converters and control CRT purity auto compensation by using 3 ADC. There is timer
sensor, temperature sensor, and magnetic sensor. MCU detect 3 factors and calculate then output data
to corner coil via U202 DAC.
b) The U702 is an EEPROM IC which stores the parameters of each mode and the user adjusting result and
also DDC data. It is controlled by IIC bus from MCU.
Mode State
ON
User/ Stand By
Factory
Suspend
PMS_OFF

4. Vertical Deflection

a) Vertical deflection Saw-tooth waveform is provided by U501, pin 12, 13 and amplified by U401 TDA4863.
b) A voltage multiplier connected to pin 3, consists of D401, C411 to avoid flyback scanning line appeared
during the vertical flyback period.
c) U401 pin 5 is output to drive vertical yoke.
Input
Sync
H V
Pulses Pulses
No Pulses Pulses
Pulses No Pulses
No Pulses No Pulses
Sync
Mute
H V
Pulse Pulse L
L L H
L L H
L L H
7-5
Output
PS
1 2 0 1
H H Depend on fH
L Pulse L H
L Pulse L H
L Pulse L H
CS
2 3 4
L H L
L H L
L H L