Trouble Shooting Table - Sharp LC-37HV6U Service Manual

TROUBLE SHOOTING TABLE

AVC System
Is the power cord connector connected to the main body
correctly?
YES
Is the fuse (F701) normal?
YES
Is the BU+5V line (pin (9) of P1702) normal?
YES
Are the wire harness, FFC, etc. in the set connected
correctly?
YES
Are there voltage variations on the OVP line (pin (3) of
P1702) just after the power is turned ON?
YES
Are each DC/DC converter output and MOS-FET (Q1701,
Q1702, Q1703 and IC1706) normal?
YES
Replace IC1702.
Power is not supplied in spite of power-on operation being performed. (The front LED does not turn green from red or blinks in red.)
Are the connectors MDR (white) and DVI (gray) of the
system cable connecting the Display and AVC System
connected correctly?
YES
Are the power SW on the AVC System side and the power
SW on the Display side turned ON?
YES
Are the voltages on the UR+6V, UR+10V and UR+13V
lines (pins (13), (1) and (17) of P1702) normal?
YES
Are the D+1.8VCV (pins (5) and (6) of P1701), D+3.3V (pin
8 of P1701) line, A+5V (pin 3 of P1701) and D+5V (pin (1)
of P1701) normal?
NO
YES
Is D_POW (pins (32), (33) and (34) of IC1702, pin
(2) of IC1704 and pin (2) of IC1705) set to "H"?
NO
Check the line of D_POW (pin (6) of main
PWB IC1503).
Check if the wire harness, FFC, etc. in the set are
connected correctly.
Power is not supplied. (The front LED does not come on.)
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
43
Connect the power cord correctly and turn ON the power
SW.
Replace the fuse. If the fuse blows when the power SW is turned
ON, replace D701 and IC 701 and perform checking again.
Is there any faulty part or short-circuited circuit on the
BU+5V line?
NO
YES
Check the peripheral circuitry of IC1701.
Remove the faulty or short-circuited part and perform
checking again.
Connect the wire harness, FFC, etc. in the set correctly and
perform checking again.
Check the parts (IC701, IC721, PC702, Q702, Q703 and
D711) in the power unit.
Check each DC/DC converter output and replace MOS-FET
(Q1701, Q1702, Q1703 and IC1706).
Connect the connectors correctly and turn ON the power
again.
Turn ON the power SW on the AVC System side and the
power SW on the Display side and turn ON the power.
Is PS_ON (pin (11) of P1702) set to "H" (3.5V)?
NO
YES
Check the PS_ON line.
Are the impedances of the UR+6V, UR+10V and UR+13V
lines normal?
(Measure the resistances between pins (13), (1) and (17) of
P1702 and GND.)
NO
YES
Check the UR+6V, UR+10V and UR+13V
lines and the circuit parts on the lines.
Are MOS-FET (Q1701, Q1702 and Q1703 and REG IC
(IC1704 and IC1705) normal?
NO
YES
Replace IC1702.
Check each output line and replace MOS-FET (Q1701, Q1702
and Q1703 and REG IC (IC1704 and IC1705).
LC-37HV6U