Page 1
SyncMaster 150T 4-1
4 Troubleshooting
Notes: 1. Before troubleshooting, setup the PC’s display as below.
• Resolution: 1024 x 768
• H-frequency: 48 kHz
• V-frequency: 60 Hz
2. If no picture appears, make sure the power cord is correctly connected.
3. Check the following circuits.
• No raster appears: Audio PCB, SMPS PCB, Main PCB
• 12V develop but no screen: Main PCB
• 12V does not develop: Audio PCB, SMPS 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 No Power
Does proper DC 12V appear at
DC jack connected to CN102?
Check DC Adaptor.
Yes
No
Does proper DC 5V appear at
output Pin of IC100?
Check IC104.
Check Q101, Q102 and Q103.
Yes
No
Does proper 5V-signal
appear at Pin 42 of IC701
(SW-REG-EN)?
Check IC701 and related circuit.
(CN100, Function Key)
Yes
No
Page 2
4 Troubleshooting
4-2 SyncMaster 150T
4-2 No Video [Analog]
Check TFT-LCD panel and inventer.
Check signal cable connection.
No
Does the digital video signal appear at the
Pin 48, 45, 42, 39, 38 of IC600?
Is the Pin 1, 19 of IC701 High?
1
3 4
5
Yes
No
2
Check IC701 and related circuit.
Does the input signal appear at the
Pin 27, 28, 30, 31 and 32 of IC600?
(DHS, DVS, DEN, DCLK, LVDS-EN)
Does the analog video signal appear at
R218, R220, R222?
(RED, GREEN, BLUE)
Does the sync signal appear at the output
Pin 14, 18 of IC706? (HSYNC_IN, VSYNC_IN)
Does the input signal appear at the Pin
Pin 88, 89, 90 and 94 of IC205?
(ADC-EN,MCU-CLAMP, M_HSYNC, HSYNC_PLL)
During Power on-off, does the input signal appear
at the Pin 39, 42 of IC 205? (SDA, SCL)
Do the clock and sync signal appear at Pin 84, 80 ofIC205?
(AD_CLK, AD_HSYNC) and does the digital video signal appear
at AD_RED (7:0), AD_GRN (7:0),and AD_BLUE (7:0)?
During Power on-off, does the signal appear at the
Pin 63, 64, 65, 66 of IC501?
Replace IC501 and check related circuit.
6
OK
Yes
14
15
Yes
Yes
17
18 19
16
Yes
Yes
21
20
Yes
Check IC600 and related circuit.
Yes
Check PC and related circuit.
No
Check IC706 and related circuit.
No
Check the related circuit for these parts.
No
Check IC701 and related circuit.
No
Related IC205.
No
Check IC710 and related circuit.
No
No
7
8 9
10
11
12
13
Page 3
4 Troubleshooting
SyncMaster 150T 4-3
4-3 No Video [Digital]
Check TFT-LCD panel and inventer.
Check signal cable connection.
No
Does the digital video signal appear at the
Pin 37, 38, 39, 40, 41, 42, 45, 46, 47, 48 of IC600?
Yes
No
Check IC701 and related circuit.
Does the input signal appear at the
Pin 27, 28, 30, 31 and 32 of IC600?
(DHS, DVS, DEN, DCLK, LVDS-EN)
During Power on-off, does the signal appear
at the Pin 63, 64, 65, 66 of IC501?
Check IC501 and related circuit.
22
OK
Yes
Yes
Yes
Yes
27
26
Yes
Check IC600 and related circuit.
Yes
Check PC and related circuit.
No
Check IC706 and related circuit.
No
Check IC301 and related circuit.
No
Check IC701 and related circuit.
No
No
Does the digital video signal appear at
R314, R315, R316, R318, R319, R320, R321,R322?(IC301)
RX2+, RX2-, RX1+, RX1-, RX0+, RX0-, RXC+, RXC-
Is the Pin 1, 19 of IC701 High?
Does the sync signal appear at the output
Pin 14, 18 of IC706? (HSYN_IN, VSYNC_IN)
Is the input signal Pin 9 of IC301 high? (TMDS-EN)
Do the clock, DE, sync signal appear at Pin 44, 46, 47,of
and 48 of IC301? (T_DCLK, T_DE, T_VSYNC, T_HSYNC)
and does the digital video signal appear at
T_RED (7:0), T_GRN (7:0),and T_BLUE (7:0)?
29
28
23
24
25
Page 4
4 Troubleshooting
4-4 SyncMaster 150T
Does the input signal appear
at the Pin2, 5 and 10 of IC401?
Check IC401 and related circuit.
Yes
No
While pushing a front control
button does any pulse appear
at Pin12 of IC401?
Check IC401 and related circuit.
No
4-4 No OSD
There is video but no OSD.
Replace IC401.
Yes
Yes
31
30
32
Page 5
4 Troubleshooting
SyncMaster 150T 4-5
WAVEFORMS
2
IC301
CH1 RMS = 1.147 V
3
IC501 #27
CH1 RMS = 1.227 V
4
IC501 #28
CH1 RMS = 1.285 V
5
FT509
CH1 RMS = 1.416V
6
IC102
CH1 RMS = 3.272 V
7
IC141 #4
CH1 RMS = 3.257 V
8
IC151 #115
CH1 RMS = 2.520V
9
IC151 #117
CH1 RMS = 2.157 V
10
IC211 #21
CH1 RMS = 4.95 V
11
IC211 #26
CH1 RMS = 484mV
13
IC501 #31
CH1 RMS = 484mV
14
IC501 #32
CH1 RMS = 4.736 V
15
IC541 #5
CH1 RMS = 4.988V
16
IC161 #6
CH1 RMS = 62mV
1
IC146 #5
CH1 RMS = 1.45V
12
IC501 #30
CH1 RMS = 467mV
17
CH1 RMS = 540mV
18
CH1 RMS = 1.074 V
19
CH1 RMS = 3.518 V
20
CH1 RMS = 2.286 V
21
CH1 RMS = 4.018 V
22
CH1 RMS = 2.886 V
23
CH1 RMS = 2.882 V
24
CH1 RMS = 2.874 V
25
CH1 RMS = 2.902 V
26
CH1 RMS = 1.560V
27
CH1 RMS = 2.469 V
28
CH1 RMS = 2.995 V
29
CH1 RMS = 2.849 V
30
CH1 RMS = 3.903 V
31
CH1 RMS = 3.162 V
32
CH1 RMS = 3.311 V
Page 6
Memo
4 Troubleshooting
4-6 SyncMaster 150T
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