No Bnc Video - Samsung 820DXn Service Manual

4. Troubleshooting

4-5. No BNC Video

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