Service manual

MODEL: L423FR
Page 31
2. No picture displayed and picture errors.
Note ) It applies when there is no screen display or an unusual screen is outputted, although
24V(Pin1,2 of J9A00) from PWB-POWER is outputted normally and the back light is turned on.
*Input source changes in following order with DEVICE UP button of remote control or DEVICE
button of front switch.
Component Input PC HDMI
2-1. No picture displayed and picture errors of all input.
YES
Is all harness connected correctly?
(especially between PWB-MAIN
and LCD PANEL (J402-LCD))
Poor harness connection or
defective cable.
NO
NO
YES
Are the specified voltages available at the
connectors below?
CN
Name
Pin No. Voltage
S5V J8A0 8 5Vdc
S3.3V J8A0 9,10 3.3Vdc
4.5V J8A0 11 3.3Vdc
Psave1* J8A2 2 3.3Vdc
Psave2* J8A2 3 3.3Vdc
Psave3* J8A2 4 3.3Vdc
* control signal of D3.3V
Problem is in the following
circuit (and peripheral
circuits) .
Voltage with
problem
PWB
including
the circuit
in problem
S5V DCDC
S3.3V DCDC
4.5V DCDC
Psave1 MAIN
Psave2 MAIN
Psave3 MAIN
*When it cannot still fix, it may have a problem with LCD-Module.
Problem is in IC300 or IC400 or their
peripheral circuits.
Please exchange PWB-MAIN