Samsung GH19BS Troubleshooting
GH19B* 4-1
CONFIDENTIAL
4-1 Troubleshooting
Notes: 1. Before troubleshooting, setup the PC’s display as below.
• Resolution: 1280 x 1024
• H-frequency: 63 kHz
• V-frequency: 75 Hz
2. If no picture appears, make sure the power cord is correctly connected.
3. Check the following circuits.
• No raster appears: Stand PCB, Main PCB
• 12V develop but no screen: Main PCB
• 12V does not develop: Main PCB
4. If you push and hold the Exit(–) button for more than 5 seconds, the monitor automatically turns back
to the factory preset.
4-1-1 No Power
Does proper DC 12V appear at
Pin 1, 2 of CN503?
Change power apaptor.
Yes
No
Does proper DC 5V appear at
Pin 3 of IC522?
Check IC522 and related circuit.
Yes
No
Does proper DC 3.3V appear
at Pin 3 of IC523, IC510 and DC 2.5V
appear at Pin 3 of IC104?
Check IC523, IC510, IC104
and related circuit.
Yes
No
Does proper DC 5V,
appear at Pin 3 of IC524?
Check IC524 and related circuit.
Check IC521.
Yes
No
4 Troubleshooting
4-2 GH19B*
CONFIDENTIAL
4-1-2 No Video [Analog]
Check signal cable and connection.
Check PC Signal.
No
No
No
Does the analog video signal appear at
R718, R717, R716? (RED, GREEN, BLUE)
Yes
Check R582, R211
and related circuit.
Check PC Signal.
Does the sync signal appear
at Pin 4 of R582 and R211?
(A_H*V_SYNC, A_V_SYNC)
No
Check IC521 and related circuit.
No
Check IC301 and related circuit.
No
Yes
During power on-off, does the input signal appear
at Pin 14, 15, 17, 18, 20, 21 of IC521?
(HCLK,HFS,HDATA(0),HDATA(1),HDATA(2),HDATA(3))
Yes
Does the video signal
appear at the output port?
10 11
Does the video signal appear
at the Pin 48, 47, 46, 45, 42, 41, 40, 39, 38, and 37 of
IC401 and IC402?
Yes
Does proper ‘High’ appear at ‘Collector’ of Q108?
Check TFT-LCD panel and Inverter.
Yes
Replace IC401 or IC402.
Yes
9 8 7 6
5
Check Q108, IC521 and related circuit.
No
Does the input signal appear at Pin 27, 28, 30, and 31
of IC401 and IC402
(DHS,DVS,DEN,DCLK)
?
4 3 2
1
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