ViewSonic Va703m4 Service Manual

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4. Circuit Description 
A. AC-DC CONVERTER 
The power supply with a high-integ rated green-mode PWM controller provides several features to 
enhance the performance of  power flyback converters. 
U801 is a PWM controller and provides many protection functions. 
U802 is a photo couple to transfer the feedback signa l from the second side which U803 detected both of 
the output DC voltage on 5V and 24V. 
Z802 detected the working...

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„  ADC: 15 pins 
    Name 
I/O Pin No  Description  Note 
ADC_GND AG 27 ADC ground   
ADC_REFIO  AP  28  ADC band-gap voltage de-coupling  1.20V 
ADC_VDD AP 29 Analog power  (3.3V) 
BLUE+  AI  30  Analog input from BLUE channel   
BLUE-  AI  31  Analog input ground from BLUE channel  
ADC_GND AG 32 ADC ground   
SOG/ADC_TEST  AIO 33  SOG in/ADC test pin   
GREEN+  AI  34  Analog input from GREEN channel   
GREEN-  AI  35  Analog...

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„ Display & TCON/VIDEO-8 Port: 54 pins 
■:LVDS+RSDS+TTLO  ■:RSDS+TTLO  ■:RSDS+TTLIO ■:TTLO  ■:TTLIO  
Pin 
NO.  6-bits 
Dual RSDS  6 bits   
Single RSDS  8/6 bits 
Dual/Single  LV D S   8 bits 
Dual/Single  TTL  6 bits 
Dual/Single  TTL  Note 
51 S[3] / 
TCON[2] / 
PWM2 
S[3] / 
TCON[2] / 
PWM2 
S[3] / 
TCON[2] / 
PWM2 
S[3] / 
TCON[2] / 
PWM2 
S[3] / 
TCON[2] / 
PWM2 
(1), (2), (3)/ 
2mA 
52 S[2] / 
TCON[3] 
S[2] / 
TCON[3] 
S[2]...

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89 AB1P NC TECP ABLU [3]/T18ABLU [3]  
90 AB1N NC TECN ABLU [2]/T19ABLU [2]  
91 ACLKP NC TEBP ABLU [1]/T20TCON [1]  
92 ACLKN NC TEBN ABLU [0]/T21TCON [0]  
93 AG3P NC TEAP AGRN [7]/T22AGRN [7]  
94 AG3N NC TEAN AGRN [6]/T23AGRN [6]  
99 AG2P TCON [11] NC AGRN [5]/T24AGRN [5]  
100 AG2N TCON [10] NC AGRN [4]/T25AGRN [4]  
101 AG1P TCON [9] NC AGRN [3]/T26AGRN [3]  
102 AG1N TCON [8] NC  AGRN [2]/T27AGRN [2]  
103 AR3P TCON [7] NC...

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„  TMDS: 18 pins 
    Name  I/O  Pin No  Description 
Note 
TMDS_TST/ PWM1  AIO 9  TMDS_TEST Pin / PWM1 / 
Power-on-latch for serial / parallel port  
TMDS_GND G 10    
TMDS_VDD P 11   (3.3V) 
EXT_RES    A  12  Impedance Match Reference.     
TMDS_VDD P 13   (3.3V) 
RX2P  I  14  Differential Data Input   
RX2N  I  15  Differential Data Input   
TMDS_GND G 16    
RX1P  I  17  Differential Data Input   
RX1N  I  18  Differential...

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„  DDC Channel: 4 pins 
    Name  I/O  Pin No  Description  Note 
DDCSCL / TCON [0] / 
BBLU [1]  I  46  DDC serial control I/F clock / TCON [0] / 
TTL BBLU [1]  (2), (3), (5) 
DDCSDA / TCON [1] / 
PWM1 / BBLU [0] IO  47  DDC serial control I/F data input / output 
/ TCON [1] / PWM1 / TTL BBLU [0]  (1), (2), (3), (5), (6), 
(8)/ 8mA /no slew 
DDCSCL2 (HDCP) / 
TCON [5] I  126  DDC serial control I/F cl
ock / TCON [5]  (2), (3), (5)...

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C, MTV512M 
The MTV512M micro-controller is an 8051 CPU core 
embedded device especially tailored for flat panel 
display applications. It includes an 8051 CPU core, 
768-byte SRAM, 4 channels of 6-bit ADC, 3 external 
counters/timers, 6 channels of PWM DAC, VESA 
DDC interface, and a 64K-byte internal program 
Flash-ROM memory in 44-pin PLCC package 
FEATURES 
• 8051 core, 12MHz operating frequency with 
single/double CPU clock...

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5. Adjustment Procedure 
 
 1. Function test 
1.1 products 17” LCD Monitor 
1.2 test equipment 
Color video Signal& pattern (Or PC with SXGA resolution and a sound card) 
1.3 Test Condition  Before function test and alignment ,each L CD Monitor should be warmed up at least 
30 minutes with the following conditions:  A: in roon temperature 
B with full white screen ,RGB ,and black 
C. with cycled display model: 
1280 x 1024 @ 60Hz 
1.4 Test display& Pattern  1.4.1 Compatible...

 
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