User manual LG LAC-M1600 R SERVICE MANUAL

[. . . ] 3) Connecting a test substitute in parallel with an electrolytic capacitor in the instrument. CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explosion hazard. Do not defeat any plug/socket B+ voltage interlocks with which instruments covered by this service manual might be equipped. Do not apply power to this instrument and or any of its electrical assemblies unless all solid-state device heat sinks are correctly installed. Always connect a test instrument's ground lead to the instrument chassis ground before connecting the test instrument positive lead. [. . . ] Use only a grounded-tip soldering iron to solder or unsolder ESD devices. 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. Do not remove a replacement ESD device from its protective package until immediately before you are ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive materials). Immediately before removing the protective material from the leads of a replacement ESD device, touch the protective material to the chassis or circuit assembly into which the device will by installed. CAUTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHER SAFETY PRECAUTIONS. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity sufficient to damage an ESD device). CAUTION. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED "DANGEROUS VOLTAGE" THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK. THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. - 1-3 - SPECIFICATIONS 1. RADIO SECTION Frequency range Intermediate frequency Usable sensitivity Signal to noise ratio 3. 4 x 4 or 8 x 4 NOTE: The design and specifications are subject to change without notice in the sourse of product improvement. FM 65. 0~74. 0MHz(Optional), 87. 5~108MHz 10. 8MHz 10dBµV 55dB AM(MW) 522~1, 620kHz (Optional:530~1, 710kHz/ 520~1, 620kHz) 450kHz 28dBµV 45dB - 1-4 - SECTION 2. Q9001, Q902, Q903, Q904, PN503, IC507, IC506, IC508 YES NO Does initial reading occur? Check laser circuitry. [. . . ] (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. SPINDLE DRIVE AND MOTOR WAVEFORM IC501(21), IC504(12) during TOC reading #2. [. . . ]