Zenith XBS448 Servisní příručka

CONTENTSSECTION 1 . . . . SUMMARYSECTION 2 . . . . CABINET & MAIN CHASSISSECTION 3 . . . . ELECTRICALSECTION 4 . . . . MECHANISM OF VCR PARTSE

2-65. Packing Accessory SectionBATTERY808CABLE, COAXIAL806CABLE SET ASS'Y, RF810OPTIONAL PARTS803A803B803C820 PLUG ASS'Y 1WAY(BLACK)OWNER&ap

Adjustment Procedure1) Travel the tape and check the bottom surface of thetape travels along with the guide line of the lower drum.2) If the

4-16DECK MECHANISM ADJUSTMENT8.3Fig. C-5-1A/C Head BaseFig. C-5-2Height AdjustmentScrew(B)Tilt AdjustmentScrew(C)AzimuthAdjustmentScrew(A)X-Value Adju

Adjustment Procedure1) After releasing the auto tracking, lightly turn the fixingscrew. Turn the (+) type driver (Ø 3 ~ Ø 4) on the X-dis-tanc

Checking/Adjustment Procedure1) Play the blank tape (empty tape) and check whether theguide roller crumbles or wrinkles the tape and adjust it ifneces

PROTECTION, MAINTENANCE AND CHECK OF VIDEO FUNCTION4-19(3) F/E Head(5) Drum Assembly(Video Head)(4) Base Assembly P2(2) Tension Post(1) Supply Reel(6)

PROTECTION, MAINTENANCE AND CHECK OF VIDEO FUNCTION4-202. Essential Check and RepairRecording density of the video is far higher than the audio.Theref

PROTECTION, MAINTENANCE AND CHECK OF VIDEO FUNCTION4-215-2) Grease Applications(1) Grease Application MethodApply grease by using a cloth swab or brus

PROTECTION, MAINTENANCE AND CHECK OF VIDEO FUNCTION4-22Lever, F/R, Base, Tension GEAR AY, P2 & P3LEVER, F/RClutch Contact Part(PL-433, Yellow)Tens

MECHANISM TROUBLESHOOTING GUIDE4-23No Auto Rewind operates.Is output of the end sensor “H”? “H”: 3.5V or less“L”: 0.7V –1V or less Is voltage at both

4-24MECHANISM TROUBLESHOOTING GUIDEAuto Stop operates.(PLAY/CUE/REV)Does the T/UP or the supplyreel pulse occur?Does the pinch roller attached tothe C

3-1SECTION 3ELECTRICALCONTENTSOVERALL WIRING DIAGRAM ...3-2VCR PARTELECTRICAL ADJUSTMENTPROCEDURES...

4-25MECHANISM TROUBLESHOOTING GUIDENo tape winding is done inplay.Is the pinch roller attached to theCapstan shaft in operation of play?Check the asse

MECHANISM TROUBLESHOOTING GUIDE4-26No cassette insert is done.Does the lever assemblyswitch operate?Is the lever assembly switchspring normal?Does the

MECHANISM TROUBLESHOOTING GUIDE4-27No safe adherence of tape is done.Is cassette insert done?Does the opener lid operate?Check the assembly status of

4-28EXPLODED VIEWS100A21A23A24032109A22054A0541151161101121131141031051021061071. Front Loading Mechanism Section

EXPLODED VIEWS4-29008011 031079017032024406031021028029026A03027022003004006007014015009409013016012OPTIONAL PARTA014052. Moving Mechanism Section (1)

EXPLODED VIEWS4-30052517061056518052A055410032077076078060051064A11A120670660650680690700230800583. Moving Mechanism Section (2)

DECK MECHANISM PARTSLOCATIONS• Top View...5-1• Top View(without Tray Disc) ...5-1• Bottom

5-1DECK MECHANISM PARTS LOCATIONStarting No.11, 21, 2, 31, 2, 3, 411, 61, 2, 61, 2, 6, 81, 2, 6, 8,91, 2, 71, 2, 71, 21, 2 ,131, 2, 13, 141, 2, 7, 12,

5-2DECK MECHANISM DISASSEMBLY1.Holder Clamp (Fig. 5-1)1) Release 2 Screws(S1).2) Unhook 2 Locking Tabs(L1).3) Lift up the Holder Clamp and then separa

3-2OVERALL WIRING DIAGRAMPMC01CFGCAP Vcc5.2VACAP REV’H’V-limitMOTOR GNDS.GNDDRUM(L/M)VccCAP CTLL/M CONTROLDPG/FGDRUM CTL123456789101112123456789101112

5-3DECK MECHANISM DISASSEMBLY3.Base Assembly Sled (Fig. 5-3)1) Release 4 Screw(S2).2) Disconnect the FFC Connector(C1)3-1. Gear Assembly Feed3-2. Gear

5-4DECK MECHANISM DISASSEMBLY5. Frame Assembly Up/Down (Fig. 5-4)Put the Base Main face down(Bottom Side)1) Release the Screw(S4)2) Unlock the Locki

EXPLODED VIEWS1. Deck Mechanism Exploded View429429026010018013014017015015A011430431011A012004001002003A01A020204304304304300120214334330120120280224

3-3ELECTRICAL ADJUSTMENT PROCEDURES1. Servo Adjustment1) PG Adjustment• Adjustment And Specification• Test Equipmenta) OSCILLOSCOPEb) NTSC MODEL : NTS

3-4ELECTRICAL TROUBLESHOOTING GUIDE1. Power(SMPS) CIRCUITNO 5.3VA.Replace the F101.(Use the same Fuse)Is the F101 normal?Is the TH101normal?Is the BD1

3-5NO 5V.5.3VA Line Check.Is 5.3VA put intothe Q168 Emitter?Is about 5V put intothe Q168 Base?Is the Q169 Base“H”?NONONOCheck the PowerControl.Check o

3-62. SYSTEM/KEY CIRCUIT(1) AUTO STOP(2) The unstable loading of a Cassette tapeAuto StopDoes the SW30 waveformappear at the IC501Pin18?Do the T-UP Re

3-73. SERVO CIRCUIT(1) Unstable Video in PB MODEUnstable Video inPB Mode.Does the Noise level of thescreen changeperiodically?Do the CTL pulses appear

3-8Does the CFG signal appear at thePMC01 Pin1?Does the PWM signal appear at theIC501 Pin77?Is “DRUM CTL” 2.8V appear at thePMC01?Check the PMC01 and

3-94. OSD CIRCUIT(1) No OSD display.(2) I2C BUS CHECKKEY doesn’t working.Is 5V applied to the IC501Pin2, 3?Does LED or FLD changewhen a function butto

1-2SECTION 1SUMMARYCONTENTSPRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS ... 1-3SERVICING PRECAUTIONS ...

3-105. Y/C CIRCUIT(1) No Video in EE Mode,No Video in EE ModeDoes the Video signalappear at the IC302Pins1, 5?Is there 5V at the IC302Pin6?Replace the

3-113. Y/C CIRCUIT(2) When the Y(Luminance) signal doesn’t appear on the screen in PB Mode,Is 5V applied to the IC301Pins23, 44, 45, 52, 68, 77?Is the

3-123. Y/C CIRCUIT(3) When the C(Color) signal doesn’t appear on the screen in PB Mode,Is 5V applied to the IC301Pins23, 44, 45, 52, 68, 77?Does the f

3-133. Y/C CIRCUIT(4) When the Video signal doesn’t appear on the screen in REC Mode,YESYESYESYESYESYESNONOYESYESYESYESYESCheck system part(V.H/SW)Rep

3-146. Tuner/IF CIRCUIT(1) No Picture on the TV screenNo picture on the TVscreenDoes the Video signal atthe TU701 Pin16.YESYESYESIs +33V applied to TU

3-15(2) No SoundNo Sound.Check the Vcc of TU701 Pins3, 14.YESCheck 5.2V, 33V Line.NOCheck the Tuner SiF signal at IC801Pin57.YESCheck the Audio of IC8

3-16Check power.Check REC start “H” signalof µ-COM.Check IC501 Pin 19.(Audio Swich 30)Check the Vcc of IC801.(Pins 3, 15, 32, 46)Is Pin 30 of IC801 ov

3-17Hi-Fi REC.It is impossible to record and playbackHi-Fi Audio signal.Check Vcc of IC801. (Pins 3, 15, 32, 46)Check Power.Check ports of µ-COM.Check

3-18 3-19BLOCK DIAGRAMS1. POWER(SMPS) BLOCK DIAGRAM 1NOTES) Symbol denotes AC ground.NOTES) Symbol denotes DC chassis ground.BD101BD101PW101

1-3IMPORTANT SAFETY NOTICEThis manual was prepared for use only by properly trained audio-video servicetechnicians.When servicing this product, un

3-20 3-212. POWER(SMPS) BLOCK DIAGRAM 2FD(+)FD(-)-29VAGND33VAGND13VAGND3.8VA3.8VAGND5.3VA5.3VAGNDGND151413121110987654321TO SYSFD(+)TO SYSFD(-)TO SYS-

3-22 3-233. Y/C BLOCK DIAGRAMEP PB 'A'EP PB 'B'SP PB 'B'SP PB 'A'6459 58 57 55 54 5365677274ACCDETENVDETC-ROTR

3-24 3-254. NORMAL AUDIO BLOCK DIAGRAMIC301LA71206MSIFA_INRF_MODIC801LA72670MTUNERTU7011076DETNORMALAUDIOOUTLINE AUDIO(R) INLINE AUDIO(L) INREAR JACKR

3-26 3-275. Hi-Fi BLOCK DIAGRAMABHi-Fi/RECIC801LA72670MA.OUTTo JACKMODULATORA.OUT(To Tu)24Hi-Fi PB 'B'Hi-Fi PB 'A'Hi-Fi REC5712741

3-28 3-296. SYSTEM BLOCK DIAGRAMGNDMODE S1MODE S2MODE S3MODE S4 MODE S/WTO/FROM AVCPT-UP REELTAPE TOPSUP REEL CST.SW/REC TAP5VCS5015.3VA5.3VA

3-30 3-31NOTES) Symbol denotes AC ground.NOTES) Symbol denotes DC chassis ground.NOTE) WarningNOTE) Parts that are shaded

3-32 3-332. POWER(SMPS) CIRCUIT DIAGRAM 2

3-34 3-353. JACK, TUNER CIRCUIT DIAGRAM

3-36 3-374. A/V CIRCUIT DIAGRAM31178914526PB Y+CREC Y+CWAVEFORMAuto Tracking is failed.IC301 Pin 59 is defective.PB COLOR Signal disappear.IC301 Pin

3-38 3-395. Hi-Fi CIRCUIT DIAGRAMPBRECNo AudioIC801 Pins37, 38 aredefective.No Hi-Fi Audio23 Pin is defective.

1-4SERVICING PRECAUTIONSCAUTION : Before servicing the COMBI HOME THEATERSYSTEM covered by this service data and its supplementsand addends, read

3-40 3-416. SYSTEM CIRCUIT DIAGRAM13485 672WAVEFORMR597, C590, C589 are defective.OSD is unstable.Q501, Q503 are defective.µ-COM is unstable.X501, X50

3-42 3-437. KEY CIRCUIT DIAGRAMA B C D E F G H I J K L M N O P Q R ST

3-44 3-45• WAVEFORMS* IC301 WaveformIC301 Pins 20, 21, 22 100mV/10msec DIVVV/EE20 Main DE Emphasis Filter21 Main DE Emphasis out22 Clamp in IC301 Pin

3-46 3-47• CIRCUIT VOLTAGE CHARTEE PLAYMODEPIN NO.2.32.292.292.292.312.302.312.312.254.9310.971.921.5502.372.3902.461.733.074.9600.361.831.472.252.322

3-48 3-49PRINTED CIRCUIT DIAGRAMS1. MAIN P.C.BOARDLOCATION GUIDE

3-50 3-51LOCATION GUIDENOTES) WarningNOTES) Parts that are shaded are criticalNOTES) With respect to risk of fire orNOTES)

3-52 3-533. KEY 1(LEFT) P.C.BOARD 4. KEY 2(RIGHT) P.C.BOARD

3-54ELECTRICAL TROUBLESHOOTING GUIDE1. System operation flowPower OnNoYesYesYesNoNoNoShow LOGOTray Closed?Tray Close to Closed positionSLED Moves to I

3-552. Test & debug flowTESTCheck the POWER PARTNoYesNoYesNoNoNoYesYesYesCheck the POWER PARTCheck the regulators or diode(D501).Check the cable c

3-56ABRESET or Power On.Show LOGO?FlashMemory operatesproperly?Check connection lines between FLASH& MT1379 and the FLASH access timewhether is su

2-1SECTION 2CABINET & MAIN CHASSISCONTENTSEXPLODED VIEWS ...

3-57BNoYesOKYesYesNoYesYesYesNoYesNoNoNoNoDoesthe SLED moveto inner side when it is atouter position?Motor Driver STBYPin is High?Motor Driver STBYPin

3-58CNoNoNoNoNoNoYesYesYesYesYesYesYesYesNoNoLaser turns on whenreading disc?LD01 or LD02 outputproperly?Check the laser power circuiton MT1336 and co

3-59DYesYesNo NoYesYesYesYesYesYesNoNoNoNoNoNoFocus ON OK?Track On OK?OKPropersignals on A, B, C,D of MT1336Check connections betweenMT1336 and pick-u

3-60ENOYES YESYESNONONormalAudio outputwhen disc playback?TEST ENDAudioDAC receivedcorrect data stream?NormalAudio DACout? (IC206)Check Audio filter,

3-613. AUDIO µ-COM Circuit(DVD & AMP)YESDoes CD/DVD appearat FLT?Does CD/DVD appearat FLT?OKDoes Loading appearat FLD?POWER ONYES YESYESDoes no Di

3-62DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING1. SYSTEM 27MHz CLOCK,RESET,FLASH R/W SIGNAL1) MT1379 main clock is at 27MHz(X501)3.8V, 27MHzFIG

3-633) RS232 waveform during procedure(Downloading)TXD(J501 PIN3)RXD(J501 PIN 2)FIG 1-34) Flash R/W enable signal during download(Downloading)FRD(IC5A

3-642. SDRAM CLOCK1) MT1379 main clock is at 27MHz(X501)(IC502,IC503 PIN 35)DCLK = 93MHz, Vp-p=2.2, Vmax=2.7VFIG 2-13. TRAY OPEN/CLOSE SIGNAL1) Tray o

3-652) Tray close waveformOPEN((PDM03 PIN7)CLOSE(PDM03 PIN8)TROPEN(IC402 PIN 1)TRCLOSE(IC402 PIN 2)FIG 3-23) Tray open waveformOPEN(PDM03 PIN7)CLOSE(P

3-664. SLED CONTROL RELATED SIGNAL (NO DISC CONDITION)FMSO(2.0V/1.4V/1.0V)(IC501 PIN 19)STBY(5V) – (IC401 PIN 50)SL+(4.7V/3.6V/1.9V)(IC402 PIN 12)SL-(

2-2EXPLODED VIEWS1. Cabinet and Main Frame Section470A00A26457457471322276274A43285284283287277286280A50262261260A46A261A261A471473469467250323A464674

3-676. LASER POWER CONTROL RELATED SIGNAL(NO DISC CONDITION)MDI1(0V/180mV)(IC401 PIN 124)LD01(5.0V//3.5V)IC401 PIN 125)LD02(5.0V/3.6V)(IC401 PIN 126)F

3-68F+(IC402 PIN 9)FE(IC401 PIN 18)RFL(IC401 PIN 19)FIG 7-2 (DVD)F+(IC402 PIN 9)FE(IC401 PIN 18)RFL(IC401 PIN 19)FIG 7-3 (CD)

3-69F+(IC402 PIN 9)FE(IC401 PIN 18)RFL(IC401 PIN 19)FIG 7-4 (CD)8. FOCUS ON WAVEFORMSFE(IC401 PIN 18)FOSO(IC501 PIN12)F+(IC402 PIN 9)F-(IC402 PIN 8)FI

3-70FE(IC401 PIN 18)FOSO(IC501 PIN12)F+(IC402 PIN 9)F-(IC402 PIN 8)FIG 8-2 (CD)9. SPINDLE CONTROL WAVEFORMS (NO DISC CONDITION)DMSO(1.4V/1.8V)(IC501 P

3-7110. TRACKING CONTROL RELATED SIGNAL(System checking)TE(IC401 PIN 21)TRSO(IC501 PIN 13)T-(IC402 PIN 7)T+(IC402 PIN 6)FIG 10-1(DVD)TE(IC401 PIN 21)T

3-7211. RF WAVEFORMRFOP(2.3V/1.1V)(IC401 PIN 6)RFON(0.8V/2.0V)(IC401 PIN 7)FIG 11-112. MT1379 VIDEO OUTPUT WAVEFORMS1) Full colorbar signal(CVBS)(IC50

3-733) C(IC507 PIN 26)FIG 12-32) Y(IC507 PIN 21)FIG 12-2

1) Audio L/RFIG 13-13-7413. AUDIO OUTPUT FROM AUDIO DAC(IC206 PIN 8,5)2) Audio related SignalASDAT3(IC501 PIN 157)ABCK(IC501 PIN 148)ALRCK(IC501 PIN 1

3-751)• R311 → FRONT L2)• R303 → FRONT R3)• R309 → SURROUND L4)• R301 → SURROUND R5)• R307 → CENTER6)• R305 → WOOFER14. DVD & AMP WAVEFORMS

3-76BLOCK DIAGRAMS1. Overall Block DiagramMMDISCSPINDLEMOTORLOADINGMOTORDECK MECHANISMDVD:RF0,A,B,C,DCD:RF0,A,B,C,D,E,FPICKUPKEY InputB/PbDVD_ESETA[0

2-3952953954956955951950A9002. Woofer Speaker Section (LHS-C640W)

3-77IC402LA6560Motor DriverDVD: A,B,C,D, RFO CD: A,B,C,D, E, F,RFOSP+, SP-M/DPICKUPX501IC501MT1379EECDVDPLAYERCOMBOCHIPIC401MT1336ERF SignalProcessorF

3-783. MPEG & MEMORY Block DiagramIC505EEPROMIIC501 (MPEG + DSP )MT1379EECIC5A1FLASH MEMORY(2 M )VIDEOInterfaceAUDIOInterfaceRF ICInterfaceVCR S

3-794. VIDEO & AUDIO Block DiagramIC507VIDEO 6dBAmpIC205(OP Amp)LPF&BufferCVBSCOMPONENT (R.G.B) / (Y.Pb.Pr )SUPER VIDEO (Y/C)(R.G.B) / (Y.Pb.P

3-805. DVD & AMP Block DiagramFRONT R+-SURROUND R+-FRONT L+-SURROUND L+-CENTERWOOFERIC710STA505IC730STA505IC750STA505IC770STA505IC301PS9818IC501MT

Incomplete DigitronSystem not workingNo Video signalVideo signal YVideo signal ColorSystem not working orscreen is abnormalNo Power on3-81 3-82CIRCU

3-83 3-842. RF & SERVO CIRCUIT DIAGRAM

TUNER_LTUNER_RLC875747BC1010.1µF/50VC1022.2µF/50VL101HB-1M2012L102 HB-1M20123-85 3-863. AUDIO, µ_COM CIRCUIT DIAGRAM(DVD & AMP)

3-87 3-884. DIGITAL AMP CIRCUIT DIAGRAM (DVD & AMP)

5. PWM & CODEIC CIRCUIT DIAGRAM (DVD & AMP)3-89 3-90

2-4A7007527507517537567547557563. Speaker Center Section (LHS-C640C)

6. INTERFACE CIRCUIT DIAGRAM (DVD & AMP)3-91 3-92

3-93 3-94• CIRCUIT VOLTAGE CHARTSTOP PLAYMODEPIN NO.5.2301.7504.91NC0.540.544.9104.770.124.72000000003.240.911.65001.993.123.263.124.65NCNCNC04.913.25

3-95 3-96IC710IC507(MM1623)IC510(BUFFER)IC5A1(FLASH)IC505(EEPROM)STOP PLAYMODEPIN NO.003.01000000002.040000_00000.23000000000000000000000001.02000003.

LOCATION GUIDELOCATION GUIDE3-97 3-98PRINTED CIRCUIT DIAGRAMS1. DVD & AMP P.C.BOARD

POSITION DRAWING OF DECKMECHANISM PARTS• Top View...4-1• Bottom View ...

POSITION DRAWING OF DECK MECHANISM PARTS4-154326910812181619171315111331471535• Top View• Bottom View2121242322313231322534282729202630 241 Drum Assem

4-2DISASSEMBLY AND ASSEMBLY OF DECK MECHANISMCap, FPCDrum AssemblyCable Flat(S1)(S1)(S1)Holder FPCH1H21. Disassembly of Drum Assembly(Figure A-1)1) S

DISASSEMBLY AND ASSEMBLY OF DECK MECHANISM4-3(B)(E)(C)Plate TopArm Assembly F/LGear Assembly Rack F/LOpener DoorHolder Assembly CST(B')(H3)(A)(B)

2. Disassembly of Plate Top (Fig. A-2-1)1) Separate the right part while leaning back the (B) part ofthe plate top toward the arrow direction.2) Separ

2-5A8008518528538508578568548554. Speaker Rear/Front Section (LHS-C640T)

DISASSEMBLY AND ASSEMBLY OF DECK MECHANISM4-58. Motor Assembly L/D (Fig. A-3-1)1) Take the connector (C1) connected to the Capstan motorPCB out. 2) Re

4-6DISASSEMBLY AND ASSEMBLY OF DECK MECHANISMBrake Assembly T Reel TSpring TensionArm Assembly TensionSpring TensionReel S(H7)(H8)(H6)Fig. A-413. Brak

DISASSEMBLY AND ASSEMBLY OF DECK MECHANISM4-7Opener LidArm Assembly PinchBase Assembly P4Arm T/up(A)(B)(C)Chassis(C)(H9)Fig. A-516. Base Assembly P4 (

4-8DISASSEMBLY AND ASSEMBLY OF DECK MECHANISMChassis(S6)Belt CapstanMotor CapstanWasher(W1)Lever F/RClutch Assembly D37(L1)(L1)Suppoter CapstanFig. A-

DISASSEMBLY AND ASSEMBLY OF DECK MECHANISM4-9Gear DriveWasher (W2)Gear CamPlate SliderLever TensionLever springBase LoadingGear Sector(B)(A)(H10)(W2)

4-10DECK MECHANISM DISASSEMBLYGear Assembly P3Gear Assembly P2Base Assembly P2Base Assembly P3(A)(B)(H14)(H12)(H13)ChassisGear assembly P2 HoleGear as

DISASSEMBLY AND ASSEMBLY OF DECK MECHANISM4-11(A)(B) (C)Arm Assembly Idler JogBase TensionChassis(D)Fig. A-934. Base Tension (Fig. A-9-1)1) Release th

DECK MECHANISM ADJUSTMENT4-12• Fixtures and Tools for Service1. Cassette Torque MeterSRK-VHT-303(Not SVC part)Part No:D00-D0064. Torque gauge adaptorP

Purpose of adjustment : To make tools normally operate by positioning tools accurately.DECK MECHANISM ADJUSTMENT4-131) Turn the VCR on and take the ta

Purpose of Measuring : To measure and check the reel torque on the take-up part and thesupply part that performs basic operation of the VCR (VCP) fors