LG CF25H30N free download

File name Schematic - Main.pdf

Service Sheet of MC-74A (1/2) PART NO : 3854VA0018A-S1 DATE : Nov 24 ,'97 TP TP1 J173 CVBS/LUMINANCE CHROMA AUDIO ADJUSTMENT TEST POINT

File name Schematic - Sub.pdf

Service Sheet of MC-74A ( 2/2) PART NO : 3854VA0018A-S2 DATE : Nov 24 ,'97

File name Troubleshooting.pdf

TROUBLESHOOTING NO PICTURE/ NO COLOR Is the CVBS signal at pin6 of IC512 normal? Yes Is the CVBS signal at pin16 of IC201 normal? Yes Are the CVBS signal at pin13, 17 of IC512 normal? Yes Is the Y signal at pin28 of IC512 normal? Yes Are the R-Y, B-Y signal at pin29, 30, 31, 32 of IC512 normal? Yes Are the R,G,B signal at pin19, 20, 21 of IC512 normal? Yes Are there R,G,B signal at pin8, 9, 10 of IC511? Yes Check the IK signal at pin18 of IC512. Yes Check CPT Board. No Check IC512. No Check/Replace IC201. No Check/Replace IC201, Q201. No Check/Replace IC512. No Check/Replace IC512, IC590, IC591. No Check/Replace IC512. No Check/Replace IC511. No Check the IK Line CPT Board. NO TELETEXT Check the voltage 12V of CT75. Abnormal Normal Check the 12V line to be correct. Abnormal Check the voltage of 5V line. Check/Replace ICT75. No 4.8~ 5.2V Check if video signal is input at pin8 of ICT74. No Check if video signal is input at pin16 of IC201. Yes Check the CVBS line. Yes Check I2C Bus lines. (SDA, SCL) Check/Replace IC201. OK Check the R,G,B signal at pin15,16,17,19 of ICT74. No Check/Replace ICT74, XT75. No Yes Check the R,G,B signal at pin9,11,13,16 of ICT76. Check/Replace ICT76. Yes Check/Replace IC512. NO PICTURE/NO SOUND (RASTER OK) Is the Auto search operating? Yes No No Is the CVBS signal at pin6 of IC512 normal? Check the voltage 5V,12V,33V SDA,SCL of TUNER. OK NG Check/Replace IC512,T114 Yes GO TO NO PICTURE Block NO SOUND Block OK Check/Replace voltage, I2C Line. Check pin15, 19 of IC12, IC20. NO RASTER (SOUND OK) Check the voltage of CPT Heater Normal Abnormal Abnormal Check the voltage of 200V Line of T406 Check the voltage of HV,SCREEN of CPT Check the Heater pulse at pin 9 of T406 Abnormal Normal Normal Check/Replace T406 Check/Replace CPT Board Check/Replace Connector, FR410, FR901 NO SOUND (PICTURE OK) Check Sound system of MENU OSD 5.5/6.0/6.5 4.5 Is the voltag of pin24 of IC12 5V(High)? Yes Is the voltage of pin24 of IC12 0V(Low)? Yes A/V STEREO MODEL Is the SIF signal of pin12 of ICS17 normal? (Sound Board) No Check/Replace ICS17. Yes Check if the Audio signal at pin55 of IC512 normal. Check if the Audio signal at pin24,25 of ICS11 normal. No Check/Replace pin1 of IC512, sound Board. Yes Check if the Audio signal at pin2,5 of IC620 normal. No Check/Replace ICS11,IC512,Q514,Q515. Yes Check the Audio signal at pin7, 11 of IC620 normal. No Check/Replace ICS11. Yes Check/Replace C664, C665, Speaker. No Check the voltage of pin10, sound MUTE of pin8 of IC620. Normal MUTE No Check/Replace XS11, ICS11, ICS12, IC201. Yes Check if the Audio signal at pin9, 13 of ICS11 normal. No Check/Replace ICS11. Yes Check if the Audio signal at pin3,5 of IC620 normal. No Check the voltage of pin10, sound MUTE of pin8 of IC620. Yes Check if the Audio signal at pin7,12 of IC620 normal. Yes Check/Replace C632, C633, Speaker. RF STEREO MODEL (A2/NICAM) NO RASTER Check +B voltage at D825 CATHOD