-74-TroubleshootingNo pictureCheck following steps.No picture with all ofinput sources Check signal processing stage and LCD driving stage;Check RGB S&H signals at test points VSIG_G1, VSIG_R1,VSIG_B1.Check power supply circuit S16.5V and peripheral circuit.Check IC IC501, IC301 and peripheral circuits.No picture with PC2input source only Check IC301, IC5301 and peripheral circuit.R2, G2, B2 signals are applied at pins 172, 78, 256 and HS2, VS2signals are applied at pins 253, 66 of IC301.Check PC/AV source selecting stage and processing stage;Check IC301 and peripheral circuit.No picture with all ofcomputer input sourcesYesYesNoNoNoNoCheck AV source selecting and decoding stage;S-Video sourceCheck S-video signal (Y/C).S_CHROMA signal is applied to pin 265 of IC301, and S-Ysignal is applied on pin 262 of IC301.Composite video sourceCheck composite video signal (Video).The composite video signal is applied to pins 109 of IC301 .No picture with videoinput sourcesYes Check IC301, IC5301 and peripheral circuit.R1, G1, B1 signals are applied at pins 82, 260, 258 and HS1, VS1signals are applied at pins 331, 161 of IC301.No picture with PC1input source onlyYesCheck IC8001 , IC301 and the peripheral cir-cuits.No picture with HDMIinput sourcesYesNo