LG HB620 Service Manual

LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
- 79 -
4.4 Key sense trouble (KEYPAD)
Key Sense sequence of HB620T is :
Default condition ROW(0-4) is 2.7V → Press the key → Corresponding ROW(x) and COL(x) go to 0V
→ Scan pulse( Col → Row ) → MSM sense what key pressed.
Check R503~ R507
with no key press
Change the Main board
Yes
NO
Change the DOME SHEET
Check R503~ R507
with key press
ROW( 0- 4) is 2. 7V?
Check R503~ R507
N
O
Ye
e
s
ROW( 0- 4) ,
COL(0- 5) is 0V
?
Work well?
End
START
Check VA401, VA502~ VA512,
VA710
~ VA714, R904R908
NO
YE
S
NO
Change SIDE KE
Y
Work well?
NO
Work well?
YE
S
YES
NO
Change the Main board
Check R503~ R507
with no key press
Change the Main board
Yes
NO
Change the DOME SHEET
Check R503~ R507
with key press
ROW( 0- 4) is 2. 7V?
Check R503~ R507
N
O
Ye
e
s
ROW( 0- 4) ,
COL(0- 5) is 0V
?
Work well?
End
START
Check VA401, VA502~ VA512,
VA710
~ VA714, R904R908
NO
YE
S
NO
Change SIDE KE
Y
Work well?
NO
Work well?
YE
S
YES
NO
Change the Main board
(MENU)
KEY MATRIX
(VT CALL)
(JAVA)
HOT505HOT504
HOT503
504
VREG_MSMP_2.7V
51KR504
HOT510
503
506505
509508
502
51KR503
R505 51K R507 51K
HOT502
sharp
HOT501 star
HOT509
501
507
R506 51K
HOT507HOT506 HOT508
510
KEY_ROW[1]
KEY_COL[1]
KEY_COL[2]
KEY_ROW[0]
KEY_COL[0]
KEY_COL[3]
KEY_COL[4]
KEY_ROW[3]
KEY_ROW[4]
KEY_ROW[2]
capacitor
VA510
51p
capacitor
VA502
51p
VA503
capacitor capacitor
51p
VA505
capacitor
51p
VA506
51p51p
capacitor
VA504 VA509
capacitor capacitor
VA508
51p51p
51p
VA511
capacitor
51p
VA507
capacitor
capacitor VA512
51p
KEY_ROW[3]
KEY_COL[5]
KEY_ROW[4]
KEY_ROW[2]
KEY_ROW[1]
KEY_ROW[0]
KEY_COL[2]
KEY_COL[1]
KEY_COL[0]
KEY_COL[4]
KEY_COL[3]
1
2
3
4
CN503
100ohm
R906
R905
100ohm
100ohm
R904
VA710 EVLC14S02050
100ohm
R908
VA711 EVLC14S02050
CN504
1
2
3
VA713
EVLC14S02050
VA714 EVLC14S02050
VA712 EVLC14S02050
R907
100ohm
KEY_COL[5]
KEY_ROW[2]
KEY_COL[5]
KEY_ROW[1]
KEY_ROW[0]
VA401
EVLC18S02015
END
PM_ON_SW_N
R503~R507
VA401
VA502~VA512
R904~R908
VA710~VA714
Z3X-BOX.COM

LG HB620 Specifications

General

Brand	LG
Model	HB620
Category	Cell Phone
Language	English