Sharp GX15 Service Manual page 60

GX15
9. Back Light does not turn on.
Is VBAT voltage applied to C530?
Is back light setting for Display set to On?
Are R527 and R547 in good appearance and mounted prop-
erly?
Is approx. 10.2 V applied between LED501 anode (A) terminal
and LED503 cathode (K) terminal?
LED501, LED502, and LED503 are mounted improperly or
defective.
CONFIDENTIAL
YES
YES
YES
YES
FS502 is mounted improperly, or the fuse is blown.
Is fuse (FS502) in good appearance, mounted properly, and is
NO
there conduction?
Is IC506 in good appearance and mounted properly?
YES
Is 0.8 V or more applied to IC506 pin 4?
YES
C530, L502, and IC506 are defective.
Go to the setting as follows and set it to On:
NO
Settings → Display → Back light → Time out
NO
Does it turn on?
Not defective.
R527 and R547 are defective.
NO
IC506 is mounted improperly or defective.
NO
2 – 52
NO
YES
NO
IC506 is defective or
mounted improperly.
NO
C506, R523, R549, and
IC106 are defective or
mounted improperly.
YES