Sharp LC-30HV4U - TROUBLE SHOOTING TABLE; (AVC System)

60
LC-30HV4U
LC-30HV4D
Power cannot be turned on. (The power LED on the front panel does not light up).
Is the power cable connected properly?
Is fuse (F701) in order?
Is the BU+5V line (pin (1) of P1703) in order?
Are the wire harness and FFC connected properly?
Are DC/DC converter outputs and MOS-FET (Q1707 and
Q1708) in order?
Replace IC1703.
Does the voltage of the OVP line (pin (8) of P1702) fluctuate
after power-on?
Plug the power cable connector and retry to turn on the
power.
Replace the fuse and retry to turn on the power. If the fuse burns,
check VA701, D701 and IC701 and replace if necessary.
Check the BU+5V line for correct impedance. (Measure the
resistance between Pin 1 and GND).
Check connections of the wire harness and FFC and
reconnect if necessary.
Check power supply internal devices (IC701, IC721, PC702,
Q702, D708 and D705).
Check DC/DC converter output lines and MOS-FET (Q1707
and Q1708) and replace if necessary.
The power does not turn on even through the power button is pressed. (The red power LED on the front panel does not turn green or
is blinking red).
Remove the cause of fault or
short-circuit.
Check IC1702 and its
peripheral circuits.
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
Is the system cable connected properly between the Display
and the AVC System (DISPLAY OUTPUT1 and DISPLAY
OUTPUT2)?
Reconnect and retry to turn on the power.
Are the power switches of the Display and AVC System on?
Turn on the power switches of the Display and AVC System.
Are the UR+6V, UR+10V and UR+13V lines (pins (1), (2), (7)
and (9) of P1702) in order?
Are the D+1.8VCV line (pins (5) and (6) of P1701), D+3.3V
line (pin (8) of P1701), D+5V line (pin (1) of P1701) and
A+5V line (pin (3) of P1701) in order?
Check the wire harness and FFC for proper connection.
Is PS_ON (pin (3) of P1702) pulled high (3.5V)?
Is D_POW (pins (32) and (34) of IC1703, pin (2) of IC1704
and pin (2) of IC1705) pulled high?
Is the impedance of the UR+6V, UR+10V and UR+13V lines
correct? (Measure the resistance between pins (1), (2), (7), (9)
of P1072) and GND).
Check the PS_ON line.
Check the UR+6V, UR+10V and
UR+13V lines and devices on the
lines.
Are MOS-FET (Q1707 and Q1708) and REG. IC (IC1704 and
IC1705) in order?
Check the D_POW line (pin (6) of
IC1503).
Check each output line and replace MOS-FET (Q1707 and
Q1708) and REG. IC (IC1704 and IC1705).
Replace IC1703.
TROUBLE SHOOTING TABLE
(AVC System)