Troubleshooting Table - Sharp LC-32GD4U Service Manual

<Power supply>
No power supply (Front LED is off) or no power-up (Front LED does not change from red to Blue)
Is the power supply cord properly connected to the main unit?
YES
Are F1701, F1702, and F1703 normal?
YES
Is the output voltage of BU+6V line (pin 4 of PO terminal) normal?
YES
Are the wire harness, FFC, etc. in the set connected properly?
YES
Is a voltage of about 380 V applied to C4701 and C5701 when
power is turned on?
YES
Is a voltage of 15 V applied to both inverter lines (INV_15V-1 and
INV_15V-2) after power is turned on?
YES
Are all power supply circuits for DC/DC converter output normal?
Check or replace DC/DC converters and lines.
URB6V (IC6753)
BS10V (IC6752)
UR10V (IC5752)
UR6V/5V (IC5754 / IC6755)
1.8 V/3.3 V/35 V (IC6756)
• Power switch: Top panel
(Main) Power (DC cutoff: Detected by microprocessor)
[Scheme of power supply system]
Triac
Backup
[(Main) Power OFF sequence]
1) (Main) Power OFF (DC switch)
2) (Main) Power shutoff is detected by the monitor microprocessor port.
(Power shutoff detection line and power (receiver) detection line are used separately for each purpose.)
3) Standby request (power cord) is sent to Seine from the microprocessor.
4) Seine shutdown process
5) Reception of shutdown permission from Seine
6) Monitor microcomputer turns off the relay to enter the standby mode.
TROUBLE SHOOTING TABLE
NO
NO
NO
NO
NO
NO
NO
DTV
(UR+6V)
Seine
Main
PS-ON
Monitor microprocessor
Reconnect the power supply cord and turn on the power.
Replace F1701, F1702, and F1703, and then turn on the power.
If a fuse still blows, replace Z1701, Z1702, D1701, TRA1701,
.
D1702, D1703, and D2703
In stand-by, is a voltage of about 170 V applied to C3701?
Check the oscillation side (primary side) and the commutation
side (secondary side) of the BU5V system power supply circuit.
Is there any broken part or short-circuit on BU6V line?
Remove the broken part or short-circuit and check again.
Reconnect the wire harness, FFC, etc. and check again
Check the 380V system power supply circuit.
(L2701 - 3, IC2701 - 2, Q2701 - 8, D2701 - 2, D1704, PC2701, etc.)
Check the oscillation side (primary side) and the commutation
side (secondary side) of each power supply circuit for the
inverters (INV_15V-1 and INV_15V-2).
Check the oscillation side (primary side) and the commutation side
(secondary side) of each power supply circuit for DC/DC converters.
(Main) Power
41
LC-32GD4U
LC-37GD4U
YES
YES
YES
.