4. Troubleshooting 4-1. Troubleshooting 1. Before troubleshooting, setup the PC `s display as below. · Resolution: 1360 x 768 · H-frequency: 65 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: Function PBA, Main PBA, I/P PBA · 5V develop but no screen: Main PBA · 5V does not develop: I/P PBA 4. If you select Brightness adjust menu and push the " returns to factory reset. (Enter/Source)" button for 5 seconds, the monitor automatically
4-1
4. Troubleshooting
4-2. No Power Symptom - When turning on the Power button after connecting the power, the LED at the front of the monitor does not operate. - Check the IP board power fuse and the IP board output power. Major checkpoints - Check the connections for the IP board and the Main board inside the monitor. - Check the Main board power part and check also whether there is any abnormal output at other output terminals.
CN600
IC602
IC601 Main Board Front Yes Check function assy.
Diagnostics
When Pin 4 of CN600 is 0V, Does proper DC 14V appear at pin 5 of CN600? Yes When pin 1 of IC 601 is DC 5V, Proper DC 3.3V appear at pin 3 of IC 601 Yes When pin 3 of IC 602 is DC 5V, Proper DC 1.8V appear at pin 2 of IC 602 Caution
No
Replace IP board.
No
Check IC 601 and related circuit.
No
Check IC 602 and related circuit.
Make sure to disconnect the power before working on the IP board.
4-2
4. Troubleshooting
4-3. No Video (Analog) Symptom Major checkpoints -Though the LED power turns on, the screen is blank when connecting the VGA cable. - Check the D-sub 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.
CN400
X201
IC200
R111,R114,R118
Main Board Front Check signal cable connection and power. Yes Diagnostics X1 oscillate proprely? Yes Is there R,G,B input at R111,R114 and R118? Yes Is there Hsync, Vsync waveform at Pin 32,33 of IC200? Yes Does the output signal appear at Pin 17~20, 22~27 of CN400? Yes There are DC 5V at Pin 1, 2 and 3 of CN400? Yes Replace LCD Panel. Caution Make sure to disconnect the power before working on the IP board. No Check PANEL_EN SIGNAL at R223 is High(On:High) and BL_EN signal at R601(ON: Low) is Low No Check CN400 and related circuit. No Check IC200 and related circuit. No Check input part. No Replace or check related circuit.
4-3
4. Troubleshooting
4-3-1. Circuit diagrams and waveforms (Analog) when no screen is displayed on the monitor
4-4
4. Troubleshooting
4-4. Faults and Corrective Actions Fault Photo Symptoms and Corrective Actions Symptoms: DVI signals are not recognized. Causes: This fault occurs when the PC does not recognize the mode information because the DVI DDC has not been input to the monitor. Remarks * Refer to the Training Manual for information on inputting the DVI DDC.
Corrective Actions: Input the DVI DDC to the monitor. Symptoms: When the monitor is turned on, only a full white pattern is displayed continually regardless of the signals. Causes: This fault occurs when only the lamp power is supplied and no video signals are input to the panel due to a fault or incorrect connections of the LVDS cable. * A full white pattern is a feature of the TN panel and is displayed when no video signals are supplied.
Corrective Actions:Replace or reconnect the LVDS cable correctly so that video signals can be supplied to the panel.
4-5
4. Troubleshooting
4-5. Adjustment 4-5-1. Service Adjustment Conditions 1. Precautions before starting Service Adjustments 1) Check whether the adjustment devices are working correctly. 2) Ensure a sufficient work space for disassembling the monitor. 3) Prepare a soft support for disassembling the monitor. 2. Entering Service Mode Entering: Exiting: Menu Power OFF Brightness 0 Power ON Contrast 0 Hold down the Enter button for five seconds
3. Basic Service Items to perform after Replacing a Board 1) Check the state of the PC color adjustment. 2) Enter the DDC data. (Enter both analog and digital data.) 3) Check whether the MCU code that corresponds to the model has been entered. 4) After completing your work in service mode, reset the monitor and switch it off. 4. How to execute DDC 1) Enter the DDC EDID data when the AD board is replaced. 2) Download the DDC input program and the DDC file that corresponds to the model from the Quality Department of Samsung and install it using a jig as shown in the figure below, and then enter the data. Monitor needing adjustment
MTI-2031 DDC Parallel Connector (25P Cable)
Connect Monitor (Signal Cable)
4-6
4. Troubleshooting
4-5-2. Service Function Spec. Service Mode (Entering) 1. Set both the brightness and contrast to 0. 2. Hold down the