ViewSonic VA702B Service Manual - Page 24

4. Power On/Off Sequence 4.1 Hardware Power ON When power cord is plugged into AC socket, SMPS starts work and provides U105 and U106 with VCC5V. When VCPU inputs to U105, U105 resets circuit active, sets U105 all registers to preset modes, and then U105 #43 sends out a HWRESET signal voltage to reset U104, and then monitor goes into stand-by mode. That means hardware power on has been completed. 4.2 Software Power ON/OFF When press power key, U105 #24 recieves low pulse, and sends out "Power on/off" order back to U104, and then U104 will do the power on/off. - If Power ON, U105 #6 (LED_Green) will send out High potential, and then LED green on. - If Power OFF, U105 #7 (LED_Orange) will send out High potential, and then LED Orange on. The Panel_Vcc, Backlight_En, CLK/DATA output to panel will follow the following sequency. T1 (ms) T2 (ms) T3 (ms) T4 (ms) T5 (ms) T6 (ms) T7 (ms) 0.1~10 0~10 >200 >100 0~50 0.1~10 >1000 5. AC Outlet Pin Assignment 3 1 2 P801 Pin Symbol 1 L 2 N 3 E Description Live Neutral GND 6. Inner Connector Pin Assignment 6.1 CN501, CN502, CN503, CN504 (Connect to Panel Backlight, SM02B-BHSS-1-TB or equivalent) Pin Symbol Description 1 H.V. 2 L.V. High voltage for lamp Low voltage for lamp 6.2 CN101 (Power BD to Interface BD) Pin No. Symbol 1,2 +5V (VCC5V) +5.2V output 3,6 GND Ground Description ViewSonic Corporation Confidential - Do Not Copy 21 VA702-1_VA702b-1