When A Blank Screen Is Displayed (Analog) - Samsung 2493HM Service Manual

4. Troubleshooting

4-3. When a blank screen is displayed (Analog)

The LED power is on but no picture is displayed on the screen when the D-SUB cable is
-
Symptom
connected
Check if the D-SUB cable has been connected.
-
Major checkpoints Check if the LVDS cable has been connected properly to the LCD panel.
-
Check if the Inverter board has been connected properly to the lamp connector of the LCD panel.
-
①
Diagnostics
②
③
④
⑤
⑥
Caution Check only after checking if the power is disconnected at the SMPS.
4-4
① X300
Check the signal cables and
their connections.
Yes
Check if X300 is oscillating normally.
Yes
Check if R, G and B inputs are
measured at R117, R120, and R121.
Yes
Check if Hsync and Vsync are
measured at R106 and R109.
Yes
Check if Hsync and Vsync are measured
at pins AF12 and E12 of IC300.
Yes
Check if DC 5V is measured at pin 5 of
IC600.
Yes
Check if the output signal appears at
pins 8 to 30 of CN400.
Yes
Replace the LCD panel.
③ CN400
⑤ IC600
④ IC300
③ R106,R109
Main Board Front
No
No
No
No
No
No
②R117,R120,R121
Check and replace related
circuits if necessary.
Check the input part.
Check the input part.
Check the circuit around
IC300.
Check the input part.
Check the circuit around
IC300.