4-22
4. Troubleshooting
4-1-9. No Sound
Symptom
-
Video is normal but there is no sound..
Major
checkpoints
-
When the speaker connectors are disconnected or damaged.
-
When the sound processing part of the Main Board is not functioning.
-
Speaker defect.
Diagnostics
MAIN BOARD
SMPS BOARD
Does the DC B12VS
appear at CN201 PIN 7,9 - B12VS_PW ?
Does the sound data appear at
PIN - COMP2_SR_IN,COMP2_SL_IN
VIA - PC_DVI_SR_IN, PC_DVI_SL_IN (PC/
DVI)?
Does the sound data appear at
TP - SPK_ L-, SPK_L+, SPK_R-, SPK_R+?
Yes
Yes
Yes
Yes
Input the sound source properly.
Please, Contact Tech support.
Change the Main Assy.
Check CN503, CN402.
Change the Main Assy.
Check IC1111 (X5).
Change the Main Assy.
No
No
No
No
No
Check the source and
check the connection of sound cable
(Comp/AV/PC/DVI to HDMI)?
Replace speaker ?
7
Caution
Make sure to disconnect the power before working on the IP board.
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...