Acer AL1916 AL1916v Service Guide - Page 45

Power +5V C701 NC U701SOT-223 NC/LT1117-18 3 VI 2 VO 4 VO C703 + 100uF/25V +3V3 C704 NC +3V3 H1 8 7 6 9 9 18 27 36 5 5 4 4 TP H2 7 6 8 9 9 18 27 36 5 5 4 4 TP 1 GND 2 3 1 1 2 3 BL_ADJ(DC) R31 C51 R32 R29 R33 Q4 0V ~ 3.3V 4.7K 1UF 0 X X X 0V ~ 5V 4.7K 1UF X 1K 4.7K MMBT3904 BL_ADJ R31 C32 P W M 47 N.C D C 4K7 1uF +12V C706 0.1uF 3,4 +5V C707 + 100uF/25V +5V +12V 4 CN701 GND 1 GND 3 +12V 5 GND 7 +5V 9 GND 11 2 BL_ON 4 BL_ADJ 6 +12V 8 GND 10 +5V 12 GND C709 0.1uF C710 + 100uF/25V CONN VCC5V +5V R708 10K` 1/16W R710 C711 0.1uF R712 Q703 PMBS3904 +5V NC 4.7K` 1/16W R711 10K` 1/16W on_BACKLIGHT 4 1 2 3 H3 7 6 8 9 9 18 27 36 5 5 4 4 TP C705 1uF/16V + B D702 1N4148 E C D701 1N4148 Q702 CHT2907 R704 100` 1/16W R702 VCTRL 4 51` 1/16W + C702 4.7uF/16V VCC1.8 VCC1.8 4 R703 2K` 1/16W VCC3.3 3,4 +5V +5V PC5V VCC3.3 4 Recommond to used "Blue" parts circuit for VCC1.8V if you want to suppoert DDC PC5V f3unction when system power off 3,4 +5V R732 +5V 10` 1/16W R709 0` 1/16W 2 3 1 Adj_BACKLIGHT +3V3 R716 NC 4 on_Panel R706 NC R707 4.7K` 1/16W R701 1K` 1/16W R705 4.7K` 1/16W Q701 PMBS3904 C708 1uF +5V +3V3 VLCD R714 R717 10K` 1/16W 10K` 1/16W R715 NC R723 51K` 1/16W R725 4.7K` 1/16W C718 Q706 PMBS3904 C715 0.1uF 0.1uF Q704 AO3401L + C717 10uF/16V D704(SSM12L) Vf=0.38V and If=1A. So when system power on, the system loading is about 400mA (3.3V is about 200mA and 1.8V is about 200mA), So D35 changed from 1N4148(or BAT42) to SSM12L(schottky diode). D704 SMAL140 P.S: The 1N4148 Vf=0.7V~1V can't meet LDO spec. The BAT42, Vf is OK but the If=200mA(forward current) can not meet current spec. For RSDS and Panel VCC=12V VLCD 5 +5V +3V3 R721 0` 1/16W R722 NC R727 10K` 1/16W 4 on_Panel_12V +5V +5V +12V VLCD_12V R718 NC/10K R729 NC/10K R719 NC/10K R726 NC/4K7 C720 NC/0.1uF R724 51K C716 Q707 0.1uF PMBS3904 VLCD_12V 5 Q705 AO3401L + C719 NC/10uF/16V R728 NC/4K7 TO-263 D703 BAT54C U702 3 VIN 1 ADJ VOUT 2 4 VOUT C713 0.1uF AIC1084-33PM R713 NC C712 + C714 100uF/25V 0.1uF R720 0` 1/16W 12/21 MODIFY +5V +12V R730 0` 1/16W R731 NC Title Size B Date: TSUM16AK Document Number POWER Monday, May 09, 2005 Sheet VCC3.3 1 of VCC3.3 4 Rev A 5 44