LG KS20 - Checking WLAN Block

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4. TROUBLE SHOOTING
LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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.
Sta
r
t
YE
S
Change Key FPCB or
N
O
Check WLAN antenna in the Key FPCB
RF cable is connected?
Connect RF cable to RF switch
NO
YES
C
h
ec
k
S
l
eep
C
l
oc
k in
t
h
e
R
63
2
Check X600 sleep clock oscillator
N
O
YE
S
NO
C
h
a
n
ge
t
h
e
Sub
boa
r
d
YE
S
Check U600 for 1.8V, and U601 for
3.3V, and U605 for 2.6V
Check WLAN power in the C610 (1.8V),
611 (3.3V), and 613 (2.6V)
YE
S
Check WLAN_PWD and SYS_RST_L
power sequence in the R651 and C624.
N
O
Check Q603 inverter