Read Sharp LB-1085 (serv.man2) Parts Guide online
LB-1085
TROUBLESHOOTING
7 – 3
3 LAMP ABNORMALITY
*
The backlight does not light up, or lights up instantaneously but turns off soon.
Is each output
voltage supplied from
each power PWB?
No
No
Identify
the PWB
which is
not lighted
the PWB
which is
not lighted
Yes
Yes
Yes
Yes
Abnormality
Refer to "4 The power is not supplied."
No
No
Replace the abnormal parts.
Lamp OFF check
While pressing [CH_Down] + [VOL_UP] of the main unit,
forcible rise the power with AC_ON, and look for the
lighting/preheat PWB whose LED is not lighted.
While pressing [CH_Down] + [VOL_UP] of the main unit,
forcible rise the power with AC_ON, and look for the
lighting/preheat PWB whose LED is not lighted.
Use a tester to check the resistance across the HCFL
connector of the PWB which is not lighted and identify
the lamp which is open. (Normally 1.8 - 2.2
connector of the PWB which is not lighted and identify
the lamp which is open. (Normally 1.8 - 2.2
Ω).
Replace the HCFL which is open.
Is there no abnormality in the main/power interface PWB
and the related sections?
and the related sections?
Is there no abnormality in the cables and the connectors?
Is there no abnormality in the main PWB?
Is the STB signal normal?
Check the connector
BK - LB line.
Are the inverter
control PWB and
its connector cable normal?
Are each inverter PWB
/preheat PWB and
their connector cable
normal?
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