Sharp LC-42LE771E Service Manual ▷ View online
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Dimming pin should be high or square wave in open position. If it is low, please check S119
and S145 for Mstar side and panel or power cables, connectors.
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Backlight power supply should be in panel specs. Please check Q34, shown below; also it can
be checked TP108.
STBY_ON/OFF_NOT should be low for tv on condition, please check Q11’s collector.
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B. CI Module Problem
Problem: CI is not working when CI module inserted.
Possible couses: Supply, suply control pin, detect pins, mechanical positions of pins.
CI supply should be 5V when CI module inserted. If it is not 5V please check
CI_PWR_CTRL, this pin should be low.
Please check mechanical position of CI module. Is it inserted properly or not?
Detect ports should be low. If it is not low please check CI connector pins, CI module
pins.
2. CI Module Problem
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C. Staying in Stand-by Mode
Problem: Staying in stand-by mode, no other operation
This problem indicates a short on Vcc voltages. Protect pin should be logic high while normal
operation. When there is a short circuit protect pin will be logic low. If you detect logic low
on protect pin, unplug the TV set and control voltage points with a multimeter to find the
shorted voltage to ground.
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