GX20
2 – 58
CONFIDENTIAL
12. External display does not function.
Does the main display function?
Refer to Troubleshooting, “Power does not turn on.”
(see page 2-42).
Is the external display set to ON?
ON Setting by the following menu:
Settings
→
Phone settings
→
External display
→
External dis-
play On/Off.
Is external display to CN401 surely inserted?
Connector insertion defective.
Clean the connector CN401 contact point and insert the exter-
nal display again. Does it function?
Connector insertion part soiled.
Voltage of 3 V
±
0.1 V applied to CN401 27pin?
Proper appearance and mounting given to the jumper (CN401
27pin to VINT)?
Jumper (CN401 27 pin to VINT Line) defective or defective
mounting.
3.0 V
±
0.1 V output at LCD_RST (CN401 8 pin)?
IC104, C417, C473 and R413 defective or defective mounting.
Proper appearance and mounting given to C426, C427 and
C428?
Electric potential on the both ends of C426, C427and C428
normal?
Square waves output?
C426: Square waves of approx. 3 V
C427: Square waves of approx. 6 V
C428: Square waves of approx. 9 V
C426, C427, C428 and CN401 defective or external display unit
defective.
Voltage of approx 11.8 V output at CN401 29pin (TP419)?
Voltage of V0 to V4 output?
V0 (C418): Approx. 8.56 V
V1 (C419): Approx. 7.33 V
V2 (C420): Approx. 6.11 V
V3 (C421): Approx. 2.42 V
V4 (C423): Approx. 1.20 V
C418, C419, C420, C421, C423, CN401 and IC403 defective.
Control signal line to IC403, or external display unit defective.
* The backlight turns off. After a while, the voltage at TP419 becomes approx. 9 V.
External display unit defective.
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
Содержание GX20
Страница 38: ...GX20 2 32 CONFIDENTIAL Figure 64 Contact points Figure 65 Turning power on Points Push ...
Страница 91: ...GX20 3 7 CONFIDENTIAL MEMO ...
Страница 96: ...GX20 4 5 CONFIDENTIAL MEMO ...