LG LGKS20 Operating Instructions - Page 103

4. TROUBLE SHOOTING 4.9 Checking WLAN Block KS20 WLAN initial power sequence is : WLAN_PWD controlled by MSM7200 GPIO goes to high (2.6V), SYS_RST_L in the WLAN module goes to low by inverting WLAN_PWD signals -> WLAN_PWR_ON controlled by MSM7200 GPIO goes to high (2.6V) ◊ VWLAN_3.3V goes to 3.3V first ◊ VWLAN_2.6V and VWLAN_1.8V go to 2.6V and 1.8V, respectively. -> WLAN_PWD is low, and SYS_RST_L is high after all WLAN power signals go on KS20 WLAN initial operation is : 32KHZ_ON controlled by MSM7200 GPIO goes to low for turning on sleep clock oscillator -> A WLAN 32.768 kHz sleep clock starts to operate -> WLAN power goes to high -> WLAN module scans access points for network access, for which RF parts in the module start to operate -> After association process to the wireless network in the KS20 set, users can use Wireless LAN. Start Check WLAN antenna in the Key FPCB NO Change Key FPCB or YES RF cable is connected? YES Check Sleep Clock in the R632 NO Connect RF cable to RF switch NO Check X600 sleep clock oscillator YES Check WLAN power in the C610 (1.8V), NO 611 (3.3V), and 613 (2.6V) YES Check WLAN_PWD and SYS_RST_L NO power sequence in the R651 and C624. YES Change the Sub board Check U600 for 1.8V, and U601 for 3.3V, and U605 for 2.6V Check Q603 inverter Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes - 105 - LGE Internal Use Only