4-2
4. Troubleshooting
4-1-2. No Power
Symptom
-
The LEDs on the front panel do not work when connecting the power cord.
-
The SMPS relay does not work when connecting the power cord.
-
The units appears to be dead.
Major
checkpoints
The IP relay or the LEDs on the front panel does not work when connecting the power cord if the cables are
improperly connected or the Main Board or SMPS is not functioning. In this case, check the following:
-
Check the internal cable connection status inside the unit.
-
Check the fuses of each part.
-
Check the output voltage of SMPS.
-
Replace the Main Board.
Diagnostics
MAIN BOARD
SMPS BOARD
Yes
Change the 14p power cable.
No
Lamp(Backlight) Off,
power indicator LED on?
Yes
Change INVERTER/BALANCE B'D.
No
Lamp(Backlight) Off,
power indicator LED on ?
Change the Main Assy.
No
No
No
No
Yes
Does proper Stand-By DC A5V
appear at VIA - A5V_PW ?
Yes
Does proper Main DC B13V, B5V
appear at VIA - B13V_PW, B5V_PW ?
Yes
Does proper DC A3.3V
appear at VIA - A3.3V_PW ?
Yes
Does proper B3.3V, B1.5V appear at
VIA - B3.3V_PW, B1.5V_PW
Next Page..
Summary of Contents for LT20A350
Page 34: ...4 5 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 35: ...4 6 4 Troubleshooting WAVEFORMS 1 PC input V sink H sink R G B 2 LVDS output...
Page 37: ...4 8 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 38: ...4 9 4 Troubleshooting WAVEFORMS 3 HDMI input RX_Data RX_Clk 2 LVDS output...
Page 40: ...4 11 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 41: ...4 12 4 Troubleshooting WAVEFORMS 2 LVDS output...
Page 43: ...4 14 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 44: ...4 15 4 Troubleshooting WAVEFORMS 2 LVDS output...
Page 46: ...4 17 4 Troubleshooting Main Board_Bottom Main Board_Bottom...
Page 47: ...4 18 4 Troubleshooting WAVEFORMS 4 CVBS OUT Grey Bar 2 LVDS output...
Page 49: ...4 20 4 Troubleshooting Main Board_Bottom Main Board_Bottom...
Page 50: ...4 21 4 Troubleshooting WAVEFORMS 5 Compnent_Y Gray scale Pb Pr Color bar 2 LVDS output...
Page 53: ...4 24 4 Troubleshooting WAVEFORMS 7 Speaker out...
Page 70: ...4 41 4 Troubleshooting TOP BOTTOM...
Page 72: ...4 43 4 Troubleshooting Model Inch CODE P N 24 27 BN44 00450A PD27A0_BDY...