4-7
4. Troubleshooting
4-4. When a Blank Screen Is Displayed (DIGITAL)
Symptom The LED power is on but no picture is displayed on the screen when the DVI cable is connected.-
Major checkpoints
Check if the DVI cable has been connected.
Check if the LVDS cable has been properly connected to the LCD panel.
Check if the Inverter board has been connected properly to the lamp connector of the LCD panel.
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-
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Diagnostics
Main Board Front
③ CN400
① X300
②, ③
R142~R151
Yes
①
Check the signal cables and
their connections.
Yes
Check and replace related
circuits if necessary.
No
Check if X300 is oscillating normally.
Check if R, G and B signals are
measured at R144~R151.
Check the circuit around
IC300.
No
Yes
Check if a waveform appears at R142
and R143.
Check the input part.
No
Yes
Check if the output signal appears at
pins 8 to 30 of CN400.
Check the circuit around
IC300.
No
Yes
Replace the LCD panel.
②
③
④
Caution Check only after checking if the power is disconnected at the SMPS.
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