Service manual

GX30

2 – 58

CONFIDENTIAL

10. Back Light does not turn on.

FS701 is mounted improperly, or the fuse is brown.

Is VBAT voltage applied to C701? Is fuse (FS701) in good appearance, mounted properly, and is

there conduction?

C701, C703, and L701 are defective.

External dis-

play only.

Which back light does not turn on, Main or External?

Main Display only or both.

Is back light setting for External Display set to On? Go to the setting as follows and set it to On:

Settings → Phone settings

Main display → Back light

Does it turn on?

Not defective.

Is CN705 in good appearance and mounted properly? CN705 is defective.

Back light FPC or CN705 is defective.

Is the contact point of back light FPC clean?

Is back light FPC properly inserted to CN705?

Clean back light FPC and insert it again. Does it turn on?

Not defective.

Is 13 - 24 V applied between TP710 and TP711? Back light FPC is defective.

Are C790, C791, C702, C707, C713, R718, and D702 in good

appearance and mounted properly?

C790, C791, C702, C707, C713, R718, and D702 are defec-

tive.

IC707, and R707 are defective.

Is back light setting for Sub Display set to On? Go to the setting as follows and set it to On:

Settings → Phone settings

External display → Back light

Does it turn on?

Not defective.

Is 7 V applied between LED703 anode (A) terminal and

LED704 cathode (K) terminal?

IC707 is defective or mounted improperly.

LED703 and LED704 are defective.

YES