Zenith-XBV442-dvd-sm电路图 维修手册.pdf

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1、RadioFans.CN 收音机爱 好者资料库 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

2、. VOLTAGE ACROSS THE COMBINATION 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 P

3、OTENTIAL SHOCK HAZARD AND 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 CONSTITU

4、TE A RISK OF ELECTRIC SHOCK. 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 SUBJ

5、ECT OF X-RADIATION. THE ONLY 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

6、A FAILURE OF THE PIC- TURE 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

7、 IS ESSNTIAL THAT SERVICE 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

8、NO POSSIBILITY OF AN X-RADIATION 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 A

9、ND YOUR SERVICE ORGA- NIZATION 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 EXCES

10、SIVE HIGH VOLTAGE, AVOID BEING 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

11、 (WHERE USED). SUBJECT: IMPLOSION 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. SUBJEC

12、T : TIPS ON PROPER INSTALLATION 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 R

13、ADIA- TORS WHERE STEAM LEAKAGE 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

14、. MUST FOLLOW THE FACTORY 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 LEAK

15、AGE TEST ON CUSTOMIZED INSTALLATIONS. 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

16、TO ROLL A CART WITH SMALL 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 SA

17、ME OR LARGER SCREEN SIZE. 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

18、 AS THE WATER PIPE. CONDUIT. ETC PLACE THIS PROBE ON EACH EXPOSED METAL PART 1-4 SERVICING PRECAUTIONS CAUTION : Before servicing the VCR+DVD covered by this service data and its supplements and addends, read and fol- low the SAFETY PRECAUTIONS. NOTE : if unforeseen cir- cumstances create conflict b

19、etween the following servicing precautions and any of the safety precautions in this publi- cations, always follow the safety precautions. Remembers Safety First: General Servicing Precautions 1. Always unplug the VCR+DVD AC power cord from the AC power source before: (1)Removing or reinstalling any

20、 component, 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

21、 of electrolytic capacitors may result in an explosion hazard. 2. Do not spray chemicals on or near this VCR+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 cl

22、eaner, cotton-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 powe

23、r to this VCR+DVD 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.

24、 Insulation Checking 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)

25、should be more than 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 Electro

26、statically Sensitive (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

27、handling any semiconductor 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 p

28、rior to applying power 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

29、or unsolder ES devices. 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

30、devices. 6. Do not 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. Immediatel

31、y before removing 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.

32、 Minimize bodily motions 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.) SPECIFICATIONS GENERAL Powe

33、r requirements AC 120V , 60 Hz Power consumption 21W Dimensions (approx.) 16.9 X 3.1 X 10.8 (430 X 78.5 X 273 mm) (w x h x d) Mass (approx.) 8.82 lbs (4.0 kg) Operating temperature 41F to 104F (5 C to 40C) Operating humidity 5 % to 90 % Signal system NTSC INPUT ANTENNA IN 75 ohms (VHF/UHF/CATV) VHS

34、VIDEO IN 1 Vp-p 75 ohms, sync negative, RCA jack x 2 VHS AUDIO IN -6.0 dBm more than 47 kohms, RCA jack (L, R) x 2 OUTPUTS VIDEO OUT1 Vp-p 75 ohms, sync negative S-VIDEO OUT(Y) 1.0 V (p-p), 75 ohms, negative sync, Mini DIN 4-pin x 1 (C) 0.286 V (p-p) 75 ohms COMPONENT VIDEO OUT(Y) 1.0 V (p-p), 75 oh

35、ms, negative sync, RCA jack x 1 (Pb)/(Pr) 0.7 V (p-p), 75 ohms, RCA jack x 2 Audio output (digital audio) 0.5 V (p-p), 75 ohms, RCA jack x 1 Audio output (analog audio) 2.0 Vrms (1 KHz, 0 dB), 600 ohms, RCA jack (L, R) x 1 RF OUTChannel 3 or 4 (Swichable) VCR SPECIFICATIONS Head system Four head hel

36、ical scan azimuth system Timer 12-hour display type with AM, PM Tape speed SP: 33.35 mm/sec, LP: 16.67 mm/sec, SLP: 11.12 mm/sec Tape width 12.7 mm Maximum recording time SP: 2 HOURS (T-120), SLP: 6 HOURS (T-120)/8 HOURS (T-160) Rewind time About 3 minutes (T-120) Channel coverage VHF: 2-13, UHF: 14

37、-69, CATV: 1-125 (4A, A-W, W+1 - W+84, A-5 - A-1) Frequency range 20Hz to 20kHz Signal-to-noise ratio More than 43dB Dynamic range More than 88 dB Channel separation More than 60 dB DVD SPECIFICATIONS Laser system Semiconductor laser, wavelength 650 nm Frequency response DVD (PCM 96 kHz): 8 Hz to 44

38、 kHz, DVD (PCM 48 kHz): 8 Hz to 22 kHz CD: 8 Hz to 20 kHz Signal-to-noise ratio More than 100dB (ANALOG OUT jacks only) Harmonic distortion Less than 0.008% Dynamic range More than 95 dB (CD), More than 100 dB (DVD) ACCESSORY: Video cable x 1, Audio cable(L/R) x 1, RF 75-ohm Coaxial Cable x 1, Remot

39、e control x 1, Batteries x 2 Design and specifications are subject to change without notice. 1-5 2-1 SECTION 2 CABINET SW 30Hz PAL:SW 25Hz Head switching output point RF Envelope output point Play the standard test tape. 6. X- distance Adjustment Left X- distance Adjusting Hole Tilt Adjusting Screw

40、(C) Fixing Screw Height Adjusting Screw (B) Right Grove of Base A/C Purpose of adjustment : To maintain compatibility with other VCR (VCP). RF ENVELOPE OUTPUT POINT HEAD RF SWITCHING OUTPUT POINT OSCILLOSCOPE Connection Diagram CH- 2CH- 1 Azimuth Adjustment Screw(A) Checking/Adjustment Procedure 1)

41、Play the blank tape (empty tape) and check whether the guide roller crumbles or wrinkles the tape and adjust it if necessary. 2) Check that the RF envelope output waveform is flat, and adjust the height of the guide roller while playing the standard test tape. 3) Adjust the switching point. 4) Check

42、 the RF envelope output is the maximum when the tracking control locates at the center. If not maxi- mum, set up to ensure that RF envelope output becomes the maximum by turning the (+) type driver ( 3 4) on the base A/C groove. 4- 18 DECK MECHANISM ADJUSTMENT 8- 2. Check of Tape Curl and Jam Status

43、 Fixtures and tools usedConnection positionVCR (VCP) statusAdjustment position Oscilloscope Standard test tape (only for SP) Post Height Adjusting Driver Driver (+) Type 5 CH-1: PB RF Envelope CH-2: NTSC : SW 30Hz PAL:SW 25Hz Head switching output point RF Envelope output point Play the blank tape.

44、Play the standard test tape. Fine adjustment of guide roller Switching Point Tracking Preset X-distance 7. Adjustment after Drum Assembly (Video Heads) Purpose of adjustment : To adjust and stabilize the height change, X- distance change, etc depending on the guide roller after assembling the drum.

45、RF ENVELOPE OUTPUT POINT V2V1V1 V1/V MAX = 0.7 V1/V MAX = 0.8 RF ENVELOPE OUTPUT HEAD RF SWITCHING OUTPUT POINT OSCILLOSCOPE Connection Diagram Waveform CH- 2CH- 1 Checking Procedure 1) Check that locking time of the RF and Audio waveform is fallen within the measuring standard in conversion of the

46、play mode from the CUE or the REV mode. 2) Readjust the paragraph 5 and 6 if it deviates from the standard. Fixtures and tools usedMeasuring standardConnection positionVCR (VCP) status Oscilloscope 6H 3KHz Color Bar Standard Test tape Stop Watch RF Locking Time: Within 5 seconds Audio Locking Time :

47、 Within 10 seconds CH-1: PB RF Envelope CH-2: Audio output RF Envelope output point Audio output jack Play the 6H 3KHz Color Bar Standard Test tape. 8. Check of Traveling Device after Deck Assembly 8- 1. Audio, RF Normalization Time (Locking Time) Check in Play after CUE or REV Checking Procedure 1)

48、 Check there is no abnormality of every traveling post status. 2) There must be no abnormal operation of the counter in occurrence of folding of the bottom tape. There must be not abnormality of audio signal in damage of the top tape. 3) If there is abnormality, readjust the adjustment para- graph 4

49、 and 5. Fixtures and tools usedFixtures and tools usedFixtures and tools used T-160 Tape T-120 Tape There must be no jam or curl at the first, middle and end position of tape. Travel the tape at the position of its first and end. PROTECTION, MAINTENANCE AND CHECK OF VIDEO FUNCTION 4- 19 (3) F/E Head (5) Drum Assembly (Video Head) (4) Base Assembly P2 (2) Tension Post (1) Supply Reel (6) Base Assembly P3 Phenomena Replace- ment Checking Points and Cause Color beatPollution of Full-Erase Heado S/N, Color FadedPollution of Video Heado Horizontal, Vertic