When The Screen Is Blank - Samsung S19A100N Service Manual

4. Troubleshooting

4-3. When the screen is blank

Symptom
Even though the LED power turns on, the screen is blank when connecting the VGA cable.
-
Check the D-sub cable connections.
-
Major
Check whether the LVDS cable is connected correctly to the panel.
-
checkpoints
Check whether the lamp connector of the panel is connected correctly to the Main board.
-
Diagnostics
Caution Make sure to disconnect the power before working on the Main board.
4-4
CN600
Check the signal cables and their
connections.
Yes
Is X401 oscillating correctly?
1
Yes
Do the RGB inputs appear at
R107~R112?
Yes
Do the Hsync and
2
waveforms appear at pins 38, 39 of
IC400, respectively?
Yes
Do output signals appear at pins 13,14,
16,17,19,20,22,23,25,26 of CN400?
Yes
Is DC 5V measured at pins 1 ~ 5
of the CN400?
Yes
Check and replace the panel.
IC400
No
No
No
Vsync
3
No
No
CN400
IC601
X401
R107 ~ R112
Check and replace the circuits
related to X401.
Check the R107~R112 input
terminals.
Check the circuits related to
IC400.
Check the circuits related to
CN400.
Check the +5V_Panel signal
and the BL_EN signal.