Samsung SyncMaster 570B TFT, Service Manual, Page: 17 / 60

4 Troubleshooting
4-4 SyncMaster 570BTFT/580BTFT
4-3 No Video of Alternate Vertical Line
One or more even or odd vertical lines do not display.
Does the waveform appear
at Pin 20 of CN301?
Replace IC311 or check its
related circuit.
Replace LCD panel.
Yes
No
6
WAVEFORMS
Go to 4-4 No OSD Display.
4-5 User Controls Don’t Work
Check the buttons.
(SW861 ~ SW866)
Does the DC level change at
Pins 11 and 12 of IC401 when you
push the front panel button?
Yes
No
Replace IC305.
Yes Yes
No
There is video but no OSD.
Replace IC307 or check its
related circuit.
Replace IC305.
4-4 No OSD
While pushing a front control
button does any pulse appear
at Pin 12 of IC307?
No
Do sync signals appear at Pins 5
and 10 of IC307?
15 16
17
WAVEFORMS
6 CN301 #20
CH1 RMS = 1.18 V
15 IC307 #12
CH1 RMS = 2.2 V
16 IC307 #5
CH1 RMS = 1.7 V
17 IC307 #10
CH1 RMS = 4.3 V