Samsung SyncMaster BX2250, Service Manual

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4-4
4. Troubleshooting
4-3. When the screen is blank (Analog)
Symptom - Though the LED power turns on, the screen is blank when connecting the VGA cable.
Major checkpoints
- Even though the LED power turns on, the screen is blank when connecting the VGA cable.
- Check the D-sub cable connections.
- 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
Yes
Check the signal cables and
their connections.
Yes
No
Check input part
No
Check the circuits related to
IC400.
No
Check the circuits related to
CN400.
Do output signals appear at pins 8 to 30
of CN400?
No Is DC 5V measured at pins 1, 2, and 3
of the CN400?
Do the
③
Hsync and Vsync
waveforms appear at pins 32, 33 of
IC400, respectively?
②
Do the RGB inputs appear at R106,
R110, and R113?
①
Is X401 oscillating correctly?
Check and replace the panel.
No
Check and replace the circuits
related to X401.
Yes
Yes
Yes
Check the +5V_Panel signal
and the BL_EN signal.
Yes
Caution Make sure to disconnect the power before working on the Main board.