LG-DVB418-cd-sm 电路图 维修手册.pdf

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1、CONTENTS SECTION 1 . . . .SUMMARY SECTION 2 . . . .CABINET CONNECT A 1500 OHM 10 WATT RESIS- TOR, PARALLELED BY A .15 MFD. 150.V A.C TYPE CAPACITOR BETWEEN A KNOWN GOOD EARTH GROUND (WATER PIPE, CON- DUIT, ETC.) AND THE EXPOSED METALLIC PARTS, ONE AT A TIME. MEASURE THE A.C. VOLTAGE ACROSS THE COMBI

2、NATION OF 1500 OHM RESISTOR AND .15 MFD CAPACITOR. REVERSE THE A.C. PLUG AND REPEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSED METALLIC PART. VOLTAGE MEASURED MUST NOT EXCEED 75 VOLTS R.M.S. THIS CORRESPONDS TO 0.5 MILLIAMP A.C ANY VALUE EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL SHOCK HAZARD AND

3、MUST BE CORRECTED IMMEDIATELY. SUBJECT: GRAPHIC SYMBOLS THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAG- NITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOC

4、K. THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIAN- GLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. SUBJECT : X-RADIATION 1. BE SURE PROCEDURES AND INSTRUCTIONS TO ALL SERVICE PER- SONNEL COVER THE SUBJECT OF X-RADIATION. THE ON

5、LY POTEN- TIAL SOURCE OF X-RAYS IN CURRENT T.V. RECEIVERS IS THE PIC- TURE TUBE. HOWEVER, THIS TUBE DOES NOT EMIT X-RAYS WHEN THE HIGH VOLTAGE IS AT THE FACTORY SPECIFIED LEVEL. THE PROPER VALUE IS GIVEN IN THE APPLICABLE SCHEMATIC. OPERA- TION AT HIGHER VOLTAGES MAY CAUSE A FAILURE OF THE PIC- TURE

6、 TUBE OR HIGH VOLTAGE SUPPLY AND, UNDER CERTAIN CIR- CUMSTANCES, MAY PRODUCE RADIATION IN EXCESS OF DESIR- ABLE LEVELS. 2. ONLY FACTORY SPECIFIED C.R.T. ANODE CONNECTORS MUST BE USED. DEGAUSSING SHIELDS ALSO SERVE AS X-RAY SHIELD IN COLOR SETS, ALWAYS RE-INSTALL THEM. 3. IT IS ESSNTIAL THAT SERVICE

7、PERSONNEL HAVE AVAILABLE AN ACCURATE AND RELIABLE HIGH VOLTAGE METER. THE CALIBRA TION OF THE METER SHOULD BE CHECKED PERIODICALLY AGAINST A REFERENCE STANDARD, SUCH AS THE ONE AVAILABLE AT YOUR DISTRIBUTOR. 4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLY THERE IS NO POSSIBILITY OF AN X-RAD

8、IATION PROBLEM. EVERY TIME A COLOR CHASSIS IS SERVICED. THE BRIGHTNESS SHOULD BE RUN UP AND DOWN WHILE MONITORING THE HIGH VOLTAGE WITH A METER TO BE CERTAIN THAT THE HIGH VOLTAGE DOES NOT EXCEED THE SPECIFIED VALUE AND THAT IT IS REGULATING CORRECTLY, WE SUGGEST THAT YOU AND YOUR SERVICE ORGA- NIZA

9、TION REVIEW TEST PROCEDURES SO THAT VOLTAGE REGU- LATION IS ALWAYS CHECKED AS A STANDARD SERVICING PROCE- DURE. AND THAT THE HIGH VOLTAGE READING BE RECORDER ON EACH CUSTOMERS INVOICE. 5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS IN A PRODUCT WITH A PROBLEM OF EXCESSIVE HIGH VOLTAGE, AVOID B

10、EING UNNECESSARILY CLOSE TO THE PICTURE TUBE AND THE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCT LONGER THAN IS NECESSARY TO LOCATE THE CAUSE OF EXCES SIVE VOLTAGE. 6. REFER TO HV. B+ AND SHUTDOWN ADJUSTMENT PROCEDURES DESCRIBED IN THE APPROPRIATE SCHEMATIC AND DIAGRAMS (WHERE USED). SUBJECT: IM

11、PLOSION 1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTE GRAL IMPLOSION PROTECTION SYSTEM, BUT CARE SHOULD BE TAKEN TO AVOID DAMAGE DURING INSTALLATION, AVOID SCRATCHING THE TUBE. IF SCRATCHED REPLACE IT. 2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES. SUBJECT : TIPS ON PROPER INSTALL

12、ATION 1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS, CUBBY- HOLE OR CLOSELY FITTING SHELF SPACE. OVER OR CLOSE TO HEAT DUCT, OR IN THE PATH OF HEATED AIR FLOW. 2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS: OUTDOOR PATIO INSTALLATIONS WHERE DEW IS A FACTOR, NEAR STEAM RADIA- TORS WHERE STEAM LEA

13、KAGE IS A FACTOR, ETC. 3. AVOID PALCEMENT WHERE DRAPERIES MAY OBSTRUCT REAR VENTING. THE CUSTOMER SHOULD ALSO AVOID THE USE OF DEC- ORATIVE SCARVES OR OTHER COVERINGS WHICH MIGHT OBSTRUCT VENTILATION. 4. WALL AND SHELF MOUNTED INSTALLATIONS USING A COMMER- CIAL MOUNTING KIT. MUST FOLLOW THE FACTORY

14、APPROVED MOUNTING INSTRUCTIONS A PRODUCT MOUNTED TO A SHELF OR PLATFORM MUST RETAIN ITS ORIGINAL FEET (OR THE EQUIVALENT THICKNESS IN SPACERS) TO PROVIDE ADEQUATE AIR FLOW ACROSS THE BOTTOM, BOLTS OR SCREWS USED FOR FASTENERS MUST NOT TOUCH ANY PARTS OR WIRING. PERFORM LEAKAGE TEST ON CUSTOMIZED INS

15、TALLATIONS. 5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A PRODUCT ON SLOPING SHELF OR A TILTED POSITION, UNLESS THE PRODUCT IS PROPERLY SECURED. 6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE ON ITS MOUNTING TO THE CART. CAUTION THE CUSTOMER ON THE HAZ- ARDS OF TRYING TO ROLL A CART WITH SMALL

16、CASTERS ACROSS THRESHOLDS OR DEEP PILE CARPETS. 7. CAUTION CUSTOMERS AGAINST THE USE OF A CART OR STAND WHICH HAS NOT BEEN LISTED BY UNDERWRITERS LABORATORIES, INC. FOR USE WITH THEIR SPECIFIC MODEL OF TELEVISION RECEIVER OR GENERICALLY APPROVED FOR USE WITH T.V.S OF THE SAME OR LARGER SCREEN SIZE.

17、8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION CORDS, EXPLAIN THAT A FOREST OF EXTENSIONS SPROUTING FROM A SIN- GLE OUTLET CAN LEAD TO DISASTROUS CONSEQUENCES TO HOME AND FAMILY. PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS A.C. VOLTMETER GOOD EARTH GROUND SUCH AS THE WATER PIPE. CONDUI

18、T. ETC PLACE THIS PROBE ON EACH EXPOSED METAL PART RadioFans.CN 收音机爱 好者资料库 1-4 SERVICING PRECAUTIONS CAUTION : Before servicing the DVD covered by this service data and its supplements and addends, read and follow the SAFETY PRECAUTIONS. NOTE : if unforeseen circum- stances create conflict between t

19、he following servicing pre- cautions and any of the safety precautions in this publica- tions, always follow the safety precautions. Remembers Safety First: General Servicing Precautions 1. Always unplug the DVD AC power cord from the AC power source before: (1)Removing or reinstalling any component

20、, circuit board, module, or any other assembly. (2)Disconnection or reconnecting any internal electrical plug or other electrical connection. (3)Connecting a test substitute in parallel with an elec- trolytic capacitor. Caution : A wrong part substitution or incorrect polarity installation of electr

21、olytic capacitors may result in an explosion hazard. 2. Do not spray chemicals on or near this DVD or any of its assemblies. 3. Unless specified otherwise in this service data, clean electrical contacts by applying an appropriate contact cleaning solution to the contacts with a pipe cleaner, cotton-

22、tipped swab, or comparable soft applicator. Unless specified otherwise in this service data, lubrication of contacts is not required. 4. Do not defeat any plug/socket B+ voltage interlocks with whitch instruments covered by this service manual might be equipped. 5. Do not apply AC power to this DVD

23、and/or any of its electrical assemblies unless all solid-state device heat sinks are cerrectly installed. 6. Always connect test instrument ground lead to the appropriate ground before connection the test instrument positive lead. Always remove the test instrument ground lead last. Insulation Checki

24、ng Procedure Disconnect the attachment plug from the AC outlet and turn the power on. Connect an insulation resistance meter(500V) to the blades of the attachment plug. The insulation resis- tance between each blade of the attachment plug and acces- sible conductive parts (Note 1) should be more tha

25、n 1M- ohm. Note 1 : Accessible Conductive Parts including Metal pan- els, Input terminals, Earphone jacks, etc. Electrostatically Sensitive (ES) Devices Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensiti

26、ve (ES) Devices. Examples of typical ES 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. 1. Immediately before handling any semic

27、onductor compo- nent or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a commer- cially available discharging wrist strap device, which should be removed for potential shock reasons prior to applying p

28、ower to the unit under test. 2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly. 3. Use only a grouned-tip soldering iron to solder or unsolder ES dev

29、ices. 4. Use only an anti-static solder removal device. Some solder removal devices not classified a “anti-static” can generate electrical charges sufficient to damage ES devices. 5. Do not use freon-propelled chemicals. These can generate electrical charge sufficient to damage ES devices. 6. Do not

30、 remove a replacement ES device from its protec tive package until immediately before you are ready to install it. (Most replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminum foil, or comparable conductive material). 7. Immediately before removing

31、the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed. Caution : Be sure no power is applied to the chassis or circuit, and observe all other safety precautions. 8. Minimize bodily m

32、otions when handling unpackaged replacement ES devices. (Normally harmless motion such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static elec- tricity sufficient to damage an ES device.) 1-5 SPECIFICATIONS GENERAL Power requirements

33、:AC 100-240 V , 50/60 Hz Power consumption:12W Dimensions (Approx.):430 x 39 x 242 mm (W x H x D) without foot Weight (Approx.): 2.2 kg Operating temperature:5 C to 35 C (41 F to 95 F) Operating humidity: 5 % to 90 % OUTPUTS VIDEO OUT:1 Vp-p 75 , sync negative, RCA jack x 1/ SCART (TO TV) AUDIO OUT:

34、2.0 Vrms (1 KHz, 0 dB), 600 , RCA jack (L, R) x 1/ SCART (TO TV) DIGITAL OUT (COAXIAL):0.5 V (p-p), 75 , RCA jack x 1 System Laser: Semiconductor laser, wavelength 650 nm Signal system: PAL / NTSC Frequency response:DVD (PCM 96 kHz): 8 Hz to 44 kHz DVD (PCM 48 kHz): 8 Hz to 22 kHz CD: 8 Hz to 20 kHz

35、 Signal-to-noise ratio:More than 100 dB (ANALOG OUT connectors only) Harmonic distortion: Less than 0.008% Dynamic range:More than 90 dB (DVD/CD) Accessories Video cable (1), Audio cable (1), Remote control (1), Batteries (2) 2-1 SECTION 2 CABINET & MAIN CHASSIS CONTENTS EXPLODED VIEWS.2-2 1. Cabine

36、t and Main Frame Section.2-2 2. Packing Accessory Section.2-3 2-2 EXPLODED VIEWS 1. Cabinet and Main Frame Section A43 A44 A00 A45 A47 A48 A46 280 452 A42 283 260 320 465 467 465 463 463 463 463 463 280 300 463 452 A49 261 261 A 5 4 3 2 1 BCD 2-3 2. Packing Accessory Section BATTERY808 PACKING SHEET

37、804 PACKING OPTIONAL PARTS 803 806 820 OWNERS MANUAL RF CABLE 810 CABLE SET ASSY 801 REMOCON900 BOX CARTON802 PACKING803 811 812 PLUG ASSY 1WAY(YELLOW) PLUG ASSY 1WAY(BLACK) PLUG ASSY 2WAY 3-1 SECTION 3 ELECTRICAL CONTENTS FEATURES FOR MEMORY CARD READ.3-2 ELECTRICAL TROUBLESHOOTING GUIDE.3-3 1. Pow

38、er check flow.3-3 2. System operation flow .3-4 3. Test & debug flow.3-5 DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING.3-11 1. SYSTEM 27MHz CLOCK, RESET, FLASH R/W SIGNAL. .3-11 2. SDRAM CLOCK.3-13 3. TRAY OPEN/CLOSE SIGNAL.3-13 4. SLED CONTROL RELATED SIGNAL(NO DISC CONDITION).3-14 5. LENS CON

39、TROL RELATED SIGNAL(NO DISC CONDITION).3-14 6. LASER POWER CONTROL RELATED SIGNAL(NO DISC CONDITION).3-15 7. DISC TYPE JUDGEMENT WAVEFORM.3-15 8. FOCUS ON WAVEFORM.3-17 9. SPINDLE CONTROL WAVEFORM(NO DISC CONDITION.3-18 10. TRACKING CONTROL RELATED SIGNAL(System checking).3-19 11. MT1389 AUDIO OPTIC

40、AL AND COAXIAL OUTPUT (SPDIF).3-20 12. MT1389 VIDEO OUTPUT WAVEFORM.3-20 13. MT1389 AUDIO OUTPUT TO AUDIO DAC.3-21 14. AUDIO OUTPUT FROM AUDIO DAC .3-22 BLOCK DIAGRAMS.3-23 1. Overall Block Diagram .3-23 2. Power(SMPS) Block Diagram.3-24 3. SERVO Block Diagram.3-25 4. MPEG & MEMORY Block Diagram.3-26 5. VIDEO & AUDIO Block Diagram.3-27 CIRCUIT DIAGRAMS.3-28 1. Power(SMPS) Circuit DIAGRAM.3-28 2. AV/JACK Circuit DIAGRAM.3-30 3. SYSTEM Circuit DIAGRAM .3-32 4. DRIVER Circuit DIAGRAM.