Read Sharp LL-T2020 (serv.man7) Service Manual online
LL-T2020
TROUBLESHOOTING
4 – 3
(No)
(No)
(No)
(Yes)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(Yes)
(Yes)
(No)
(No)
(No)
(Yes)
(Yes)
(Yes)
(Yes)
(No)
(Yes)
(No)
(No)
(No)
(Yes)
(No)
(No)
(Yes)
(No)
(Yes)
(Yes)
Check DC+5V power supply line (PV5) ,
POWER_CTL3 signal, and circuits around
Q807.
POWER_CTL3 signal, and circuits around
Q807.
Check DC+2.5V power supply line (DV25),
POWER_CTL4 signal, and circuits around
IC802.
POWER_CTL4 signal, and circuits around
IC802.
Check DC+12V power supply line (LCDV),
POWER_CTL2 signal, and circuits around
Q803.
POWER_CTL2 signal, and circuits around
Q803.
Check clock circuit around IC501 and X501.
Clock (R508) and DE (R502) signal outputs
are normal?
are normal?
ADJUSTMENT and MODE SELECT are set
properly?
properly?
Signal waveform of test terminal LD502 is
normal?
normal?
ADJUSTMENT and MODE SELECT are set
properly?
properly?
Adjust according to "screen adjustment
procedure".
procedure".
Adjust according to "screen adjustment
procedure".
procedure".
Check circuits around IC301, IC302, and
IC402.
IC402.
Check circuits around IC701, and CN701
and LCD module.
and LCD module.
Check DC+5V power supply line (DV5A),
POWER_CTL1 signal, and circuits around
Q807.
POWER_CTL1 signal, and circuits around
Q807.
Test terminals LD405, LD523, and LD701 are
DC+3.3V?
DC+3.3V?
Signal waveform of test terminal LD565 is
normal?
normal?
Test terminals LD401, LD402, and LD403 are
DC+3.3V?
DC+3.3V?
Test terminal LD815 is DC+5V?
Test terminal LD806 is DC+5V?
Test terminal LD801 is DC+12V?
Test terminal LD501 is DC+2.5V?
LD816 is DC+12.0V?
36th pin of LC602 is in H level (DC+5V)?
The entire LCD screen is white?
The entire LCD is black?
The size of LCD screen is abnormal?
LCD screen jitters or flickers?
Check circuits around IC401.
Check circuits around IC403.
Check circuits around IC601.
Test terminal of LD701 is DC+12V?
Check circuits around X601 and IC602.
Check circuits around IC502.
Check circuits around CN701.
Check PLL circuits around IC402.
Check circuits around IC502.
4
Check inverter unit, inverter cable and their
connections.
connections.
(No)
(Yes)
When CN802 cable is removed, LD801 is
DC+12V?
DC+12V?
Check the power unit and cable and their
connections, and DC+12V power supply
line.
connections, and DC+12V power supply
line.
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