Sharp LC-32HT2U, Service Manual

Page: 34 / 148

LC-32HT2U
6 – 1
LC-32HT2U
Service Manual
CHAPTER 6.
TROUBLE SHOOTING TABLE
[1] TROUBLE SHOOTING TABLE
<Power supply>
No power supply (Front LED does not light up) and no power-up even is turned on (Front LED light up to blue)
Is the AC cord connected?
NO
Connect the AC cord and turn on the power.
YES
Are the harness and FFC connected properly?
NO
Connect the harness and FFC properly.
YES
Are F701 normal?
NO
If the fuse is blown when turning on the power after replacing F701, replace
VZ701, DS4701, F4701/F4702, F5701, Q4701/Q4702, Q5701, IC4701 and
IC5701, then recheck.
YES
Is the voltage of C4701/C4702/C4703 approx.
160V?
NO
Check if VZ701, R701, R702, R703 and DS4701 are normal.
YES
Is BU5V supplied?
NO
Do the primary side and secondary side of T5701 oscillate normally?
YES
YES
NO
Are F5702, D5705, IC5706 and D5717 out
of order? Are there defective parts on the
primary side? Is the output on
the secondary side short-cir-
cuited?
Are UR6V/UR10V/UR13V supplied?
NO
Does PS_ON (pin 1 of CN5702) become High (approx. 3.3V)?
YES
YES NO
Check the regulator circuit of UR6V, recti-
fier circuit of UR13V and DC/DC circuit of
UR10V. Is the unit set to STANDBY
MODE2? Is the main unit nor-
mal?
Is 24V supplied?
NO
Do the primary side and secondary side of T4701 oscillate normally?
YES
YES NO
Are D4705/D4706 out of order? Are there defective parts on the
primary side? Is the output on
the secondary side short-cir-
cuited?
Is PNL5V supplied?
NO
Does PNL_POW (pin 4 of CN5702) become High (approx. 3.3V)?
YES
Check the DC/DC circuit of PNL5V? Is the main unit normal?
Turn on the power again, and check if the unit
works normally.
Remarks
State of the set
PS_ON
(CN5702 )
PNL_POW
(CN5702 )
BU5V
(CN5702 )
UR6V
(CN5701 )
UR10V
(CN5701 )
UR13V
(CN5701 )
PNL5V
(CN5701 )
24V
(CN5703 )
STDBY
MODE1 High High 5V 6V 10V 13V 5V 24V
MODE2 Low Low 5V - - - - -
Power ON High High 5V 6V 10V 13V 5V 24V