Samsung 820DXn - SyncMaster - 82" LCD Flat Panel..., Service Manual, Page: 39 / 73

4-8
4. Troubleshooting
4-5. No BNC Video
Symptom The LED power turns on but the screen is blank when the BNC cable is connected.
-
Major
checkpoints
Check the BNC 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 IP board.
-
-
-
Diagnostics
CN403
IC103
ZD115~113 ID114
Main Board Front
Yes
Press the power button and
check the LED.
No
Does 3.3 V appear at ZD114 ~ 118?
Is the cable properly connected?
Reconnect the BNC cable.
No
Yes
Does the wave form appear at Pin 6
(H-sync)
⑨
And Pin 8 (V-sync)
⑩
of
IC103?
Replace IC103.
No
Yes
Does the TX** signal appear at Pin 14
and 15 of CN403?
The scaler (IC408) is
abnormal.
Replace the main board.
No
Yes
Check the cable between the main
board and panel and
replace the LCD panel.
Caution Make sure to disconnect the power before working on the IP board.