When The Screen Is Blank (Analog) - Samsung S22A350H Service Manual

4. Troubleshooting

4-3. When the screen is blank (Analog)

Symptom - Even though the LED power turns on, the screen is blank when connecting the VGA cable.
- Check the D-sub cable connections.
Major checkpoints - Check whether the LVDS cable is connected correctly to the panel.
- 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
Check the signal cables and
their connections.
Yes
① Is X401 oscillating correctly?
Yes
② Do the RGB inputs appear at R106,
R110, and R113?
Yes
Do the ③ Hsync and ④ Vsync
waveforms appear at pins 38, 39 of
IC400, respectively?
Yes
Do output signals appear at pins 8 to 30
of CN400?
Yes
Is DC 5V measured at pins 1, 2, and 3
of the CN400?
Yes
Check and replace the panel.
CN400
IC400
X401
Check and replace the circuits
No
No
No
No
No
related to X401.
Check the R106, R110, and
R113 input terminals.
Check the circuits related to
IC400.
Check the circuits related to
CN400.
Check the +5V_Panel signal
and the BL_EN signal.