Sharp AQUOS LC-26GA5H, Service Manual

Page: 35 / 167

35
LC-26GA5H/M/X
TROUBLE SHOOTING TABLE
YES
YES
YES
NO
YES
NO
YES
YES
NO
YES
NO
NO
NO
NO
NO
<Power supply>
No power supply (Front LED is off) or no power-up (Front LED does not change from red to green)
Is power cable properly connected to the main unit?
Is BU+5V line (pin (16) of CN706, pin (8) of CN707 and pin
(5) of CN708) normal?
Is there any defective part or short-circuit in BU+5V line?
Check the 15V line power circuits (T701, T702, F704, Q706-14,
PC703-4, D708-17, IC702, L710, Q733-6, D735-6, D780 and
IC706).
Check each DC/DC converter and line (IC707-11 and IC716).
Replace if necessary.
Remove the defective part or short-circuit, and repeat the check.
Is the voltage (approx. 380V) available at C709/C710 when the
power is turned on?
Is the voltage available in 15V line immediately after the power is
turned on?
Is each DC/DC converter output (IC707-711 and IC716) normal?
Reconnect the wire harness, FFC, etc. in the set properly, and
repeat the check.
Check the 380V line power circuits (L703, IC701, Q701-5, D706
and TH701).
Connect the AC cord properly, and turn on the power.
Is F701 normal?
Replace F701 and F702, and turn on the power. If the fuse is
still blown, replace VA701, D701, D702, L703, Q701, Q702 and
IC701. Then repeat the check.
Check the BU+5V line power circuits (F703,
D722, IC703, T703, PC702, D761, D784 and
IC715).
Are the wire harness, FFC, etc. in the set connected properly?
•
Power switch: Top panel
(Main) Power (DC cutoff: Detected by microprocessor)
[Scheme of power supply system]
[(Main) Power OFF sequence]
1) (Main) Power OFF (DC switch)
2) (Main) Power shutoff is detected by the monitor microprocessor port.
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.
(Main) Power
SH
Main
Relay
Monitor microprocessor Backup