Dell E1909W - Power On;Off Sequency

Service Manual
11
- Button “Menu” on front bezel connects to U105 (TSUM5PEHJ-LF-2) #50 through CN104 #1, U105
#50 Voltage is defined as “Menu”.
- Button “SELECT” on front bezel connects to U105 (TSUM5PEHJ-LF-2) #122 through CN104 #4,
U105 #122 Voltage is defined as “SELECT”.
- LED Indicator on Front Bezel
a. When press button “power”, U105 (TSUM5PEHJ-LF-2) #123 be send in low Voltage, make
Q107#3 sends out high Voltage , and then to CN01#5 on keypad, LED green on.
b. When in “Suspend” mode, U105 (TSUM5PEHJ-LF-2) #124 sends out a low Voltage, make
Q108#3 sends out high Voltage and then to CN01 #7 on keypad, LED Amber ON.
2.3.4 MATAR CHIP U105 (TSUM5PEHJ-LF-2)
- U105 (TSUM5PEHJ-LF-2) #91~#100 output 8 bit even and #77~#86 output 8 bit odd LVDS digital
data to panel control circuit through CN103.
- U105 (TSUM5PEHJ-LF-2) #73 output PPWR ”H” potential to make Q104 conducted, and then
make Q101 conducted, +5V flow to CN103#1~#3 as Panel Vdd .
- U105 (TSUM5PEHJ-LF-2) #109 output CCFL_ON/OFF ”L” potential to control Inverter on/off.
- U105 (TSUM5PEHJ-LF-2) #125 outputs Brightness “PWM” signals to control CCFL brightness.
- TCLK by Crystal 14.318MHz input to U105 (TSUM5PEHJ-LF-2) #128/#127.
- U105 (TSUM5PEHJ-LF-2)#108 is RESET signals input pin
Please refer to U105 (TSUM5PEHJ-LF-2) Pin Assignments table in page
2.3.5 Regulator Circuit
- +3.3V is generated from Regulator U101 which is supplied by+5V via R101 and through C104
filtering,
-+1.8V is generated from Regulator U102 which is supplied by+3.3V through C106 filtering,
3. FACTORY PRESET TIMING TABLE
Standard
Resolution
Horizontal Frequency
(KHz)
Vertical Frequency
(Hz)
640 x 480
31.469
59.940
640 x 480
37.500
75.000
800 x 600
37.879
60.317
800 x 600
46.875
75.000
1024 x 768
48.363
60.004
1024 x 768
60.023
75.029
1152x864
67.500
75.000
1280x1024
48.483
60.042
1280x1024
60.087
75.034
VESA
1440x900
55.935
59.887
IBM DOS
720 x 400
31.469
70.087
4. Power On/Off Sequency
Hardware power On/Off
When power cord plug into AC socket, Power provides 26V and DC_5V.
DC_5V is main voltage for panel and Regulator U101.
DC_3.3V is coming from Regulator U101, DC_3.3v is main voltage for U105. When DC_3.3V input to
U105 and U105 reset circuit active, U105 all registers will be set to default, that means finish hardware
power on.
When pull out power cord from AC socket,the system shut down instantly for no supply
Software power On/Off
- When press power key, U105 #4 receives low pulse, then U105 (TSUM5PEHJ-LF-2) will be wake up