Trouble Shooting Table - Sharp LC-37AD1E 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 (12) 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 (18) 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 monitor side turned ON?
YES
Are the voltages on the UR+6V, UR+10V and UR+13V
lines (pins (7), (20) and (4) of P1702) normal?
YES
Are the D+1.8VCV (pins (5) and (6) of P1701) line,
D+3.3V (pin (8) of P1701) line, A+5V (pin (3) of P1701)
line and D+5V (pin (1) of P1701) line 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.
EU DIGITAL power is not supplied.
Is power supplied to UR+12V (pins (5), (6), (7) and (8) of IC1781)?
YES
Is EU_D_POWER (pin (17) of P1702) set to "H"?
YES
Is the D+12V line normal?
YES
Check if the wire harness, FFC, etc. in the set are
connected correctly.
Power is not supplied. (The front LED does not go on.)
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
NO
NO
NO
43
Connect the power cord correctly and turn ON the power SW.
Replace the fuse (F701). 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 line 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 (10) 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 (7), (20) and (4) 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).
Check the UR+12V line.
Check the EU_D_POWER line.
Check the peripheral circuitry of IC1781 and Q1781
and the circuitry on the D+12V line.
LC-37AD1E