User manual LG LAC4710

[. . . ] When replacing any components, use components which have the same ratings. Components marked in the circuit diagram are important for safety or for the characteristics of the unit. Always replace with the exact components. 3) An insulation tube or tape is sometimes used and some components are raised above the printed writing board for safety. [. . . ] Further check the insulation between the blades of attachment plug and accessible conductive parts. - 1-2 - ESD PRECAUTIONS Electrostatically Sensitive Devices (ESD) Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated circuits and some field-effect transistors and semiconductor chip components. The following techniques should be used to help reduce the incidence of component damage caused by static electricity. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging wrist strap device, which should be removed for potential shock reasons prior to applying power to the unit under test. After removing an electrical assembly equipped with ESD devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly. Use only a grounded-tip soldering iron to solder or unsolder ESD devices. Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static" can generate electrical charges sufficient to damage ESD devices. These can generate electrical charges sufficient to damage ESD devices. Q371, Q372, IC403 Is u-com IC906 LCD reset circuit normal?Pin74 NO · Reset circuit defective. IC901 Surrounding circuit defective. YES Is u-com IC906 X1, X2 terminal Pin11, 12, 14, 15 input?OSC :19. 2MHz OSC :32. 768kHz YES Is u-com IC906 keyin Pin19, 20 5volt input?YES NO NO Q921, ZD910 PCB pattern defective. NO X101, X102, C101, C102, C103, C104. Is u-com IC401 Pin75, 76, 78 output waveform normal? IC906, Pin74, 75, 76 front PCB pattern defective. YES NO Is IC901 Com1, Com2, Com3 output waveform normal? IC901, Surrounding circuit PCB pattern defective. YES Display LCD connector defective. - 2-2 - 3. Initial reading is not carried out. Slide motor moves (With disc) YES NO Spindle motor turns WAVEFORM #1 YES (with disc) Does RF waveform appear?IC501 Pin49 WAVEFORM #2 NO Check the Voltage change of CN503 Pin12 (6. 4~6. 8V) YES NO NO Defective connector CN503 Defective IC501 Defective connector CN503 Defective MICOM Check the Voltage IC501 Pin23 (1. 4V~1. 8V) YES Check the Data transmission from CN503 (16, 17, 18) to CD DSP WAVEFORM #5 YES NO Check the Data transmission from CN503 Pin21 to MICOM WAVEFORM #5 YES Defective NO connector CN503 Defective IC503 Check the TRVP Voltage IC501 Pin23 YES NO Defective IC501 Check the change of SL +, SL - Voltage IC503 Pin13, 14 YES NO Defective IC503 Laser light check A ? YES Defective contact CN501 Defective PICK-UP Does FA+ waveform appear at IC501 Pin23?WAVEFORM #3 focus coil drive wareform. YES NO Does TE waveform appear at IC501 Pin24?WAVEFORM #4 TRACKING ERROR wareform YES NO Is rotation normal? NO YES Is there no dropout of RF signal? YES Defective IC501 Defective PICK-UP - 2-3 - A When laser does not light. Is "2. 4V~3. 4V" applied to pin42 of IC501?( OV 3. 4V 2. 4V) NO NO NO Is data transferred from MICOM IC ?YES Defective MICOM or CN503. Did pickup return to innermost circular?YES Does voltage appear at IC503 Pin 13, 14? NO Defective IC501. YES Defective slide motor and/or connector. [. . . ] (CN502) Does it stop at inner pick circular after shift? YES Is defect output from LMT SW applied to Pin7 of PN503?OPEN CLOSE NO Defective LMT SW and/or connector. (CN502, CN503) YES YES Defective MICOM. NO Is power supplied to laser Q541?(Q541 collector: about 1. 8V) Defective IC501 - 2-4 - B When laser light. Laser lights YES Check the signal FOCUS SEARCH of IC501 Pin25 WAVEFORM #3 YES Check the signal of IC503 Pin 15, 16 WAVEFORM #3 YES Degraded laser diode Defective PICK-UP NO Defective IC501 NO Defective IC501 C When SPINDLE motor dose not turn Check the change for SPDO Voltage of IC501 Pin21 WAVEFORM #1 Check the change for SP +, SP -, Voltage of IC503 Pin11, 12 WAVEFORM #1 YES NO Defective IC501 NO Defective IC503 Defective contact CN501 or Defective PICK-UP - 2-5 - WAVEFORMS OF MAJOR CHECK POINT #1. [. . . ]