JVC MX-G75V Service Manual Download Page 45

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MX-GT98V/MX-GT95V/MX-GT88V

MX-GT85V/MX-G78V/MX-G75V

1-45

TR1

TR3

TR4

TR6

TR5

TR7

TR9

TR10

TR8

TR20

R13

R16

R19

TR18

R14

R15

R16

TR17

R17

D12

TR12

TR11

C11

C12

R11

TR14

TR13

TR15

R12

TR41

R41

D41

D51

TR32

R31

Compar

ator

Compar

ator

D53

D52

D42

D43

SUB

STK412-010[MX-GT98V/GT95V], STK412-000[MX-GT88V/GT85V],
STK412-090[MX-G78V/G75V] (IC701) : Power amp.

Summary of Contents for MX-G75V

Page 1: ... method Adjustment method 1 2 1 3 1 4 1 5 1 29 Flow of functional operation until TOC read Maintenance of laser pickup Replacement of laser pickup Description of major ICs 1 33 1 34 1 34 1 35 49 Contents No MIC jack and MIC LEVEL volume for UN ver MX GT98V MX GT95V MX GT88V MX GT85V MX G78V MX G75V COMPACT DIGITAL VIDEO COMPACT DIGITAL AUDIO Area suffix US Singapore UN Asean SP MXGT98V SP MXGT95V ...

Page 2: ...minals knobs metal cabinet screw heads headphone jack control shafts etc to be sure the product is safe to operate without danger of electrical shock Do not use a line isolation transformer during this check Plug the AC line cord directly into the AC outlet Using a Leakage Current Tester measure the leakage current from each exposed metal parts of the cabinet particularly any exposed metal part ha...

Page 3: ...G Osynlig laserstrålning är denna del är öppnad och spårren är urkopplad Betrakta ej strålen VARO Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymättömälle lasersäteilylle Älä katso säteeseen ADVARSEL Usynlig laserstråling ved åbning når sikkerhedsafbrydere er ude af funktion Undgå udsættelse for stråling ADVARSEL Usynlig laserstråling ved åpning når sikkerhetsbryteren er avslott unngå ...

Page 4: ...r s internal power source can easily destroy the laser diode 4 Handling the traverse unit optical pickup 1 Do not subject the traverse unit optical pickup to strong shocks as it is a sensitive complex unit 2 Cut off the shorted part of the flexible cable using nippers etc after replacing the optical pickup For specific details refer to the replacement procedure in the text Remove the anti static p...

Page 5: ...wo screws B on both sides of the body Remove the metal cover from the body by lifting the rear part of the cover 1 2 3 Disassembly method Main body Removing the metal cover See Fig 1 to 3 Do not break the front panel tab fitted to the metal cover CAUTION Fig 1 Fig 2 Fig 3 A A A Metal cover Metal cover B Metal cover B ...

Page 6: ...f the body Remove the CD mechanism assembly 6 Removing the CD changer mechanism assembly See Fig 4 and 6 Prior to performing the following procedure remove the metal cover and the CD changer mechanism assembly Turn over the CD changer mechanism assembly and remove the two screws E attaching the fan 1 Removing the fan See Fig 7 To prevent damage to the CD fitting be sure to pull both the rear panel...

Page 7: ...ifier board Disconnect the wire from connector CN220 on the transformer board Remove the two screws F on the bottom of the body Release the two joints a on the lower right and left sides of the body using a screwdriver and remove the front panel assembly toward the front 1 2 3 4 5 Removing the front panel assembly See Fig 8 to 11 Fig 9 Fig 10 Fig 11 F Bottom Joint a Joint a Front panel assembly Fr...

Page 8: ... the metal cover and the CD changer mechanism assembly Remove the screw H attaching the rear cover on the back of the body Push each tab of the four joints b in the direction of the arrow and release Remove the fifteen screws G attaching the rear panel Disengage the joints c on each lower side of the rear panel using a screwdriver and remove the rear panel backward 1 2 3 4 Removing the rear cover ...

Page 9: ...body Disconnect connector CN211 and CN212 on the main board from the regulator board 1 2 3 4 Removing the main board See Fig 17 and 18 Prior to performing the following procedure remove the metal cover the CD changer mechanism assembly and the rear panel Disconnect connector CN217 on the speaker board from the regulator board 1 Removing the speaker board See Fig 19 It is not necessary to remove th...

Page 10: ... heat sink Remove the two screws K the board bracket and the voltage board 1 2 3 4 5 Removing the amplifier board voltage board heat sink See Fig 21 and 22 Prior to performing the following procedure remove the metal cover the CD changermechanism assembly and the rear panel Remove a wire clamp on the power board Disconnect the wire from connector CN218 CN219 and CN250 on the power board Disconnect...

Page 11: ...ard and speaker board Disconnect the wire from connector CN204 on the regulator board Release the wire from the stopper on the regulator board Remove the two screws M attaching the regulator board 1 2 3 Removing the regulator board See Fig 25 Prior to performing the following procedure remove the metal cover the CD changer mechanism assembly and the rear panel Disconnect the wire from connector CN...

Page 12: ...tem control board Remove the six screws P attaching the display system control board If necessary disconnect the wire from connector CN911 on the front side of the display system control board and unsolder FW915 1 2 3 4 Removing the display system control board See Fig 28 to 30 Remove the three screws Q attaching the CD eject board If necessary unsolder FW915 on the CD eject board 1 2 Removing the...

Page 13: ... surround mode knob the mic level knob and the surround woofer level knob toward the front Remove the thirteen screws S attaching the operation switch board CA MXG75V MXG78V CA MXGT85V MXGT88V Remove the twelve screws S attaching the operation switch board CA MXGT95V MXGT98V Release each tab of the seven joints g retaining the operation switch board 1 2 3 Removing the operation switch board See Fi...

Page 14: ...to performing the following procedures remove the front panel Remove the two screws B attaching the speaker tweeter on the back of the front panel 1 Removing the speaker tweeter See Fig 3 Prior to performing the following procedures remove the front panel Remove the six screws C attaching the sub panel on the back of the front panel Pull out the sub panel toward the front 1 2 Removing the sub pane...

Page 15: ...front panel Remove the eight screws D attaching the punch panel on the front of the body Remove the six screws F attaching the speaker woofer on the front of the body Remove the speaker woofer toward the front and disconnect the wire from the two speaker terminals 1 2 3 Removing the speaker woofer See Fig 6 and 7 Remove the four screws G attaching the duct on the upper side of the body Move the du...

Page 16: ...attaching the speaker tweeter on the front of the body Disconnect the wire from two speaker terminals of the speaker tweeter 1 2 Removing the supeaker tweete See Fig 2 Prior to performing the following procedures remove the front panel Remove the four screws C attaching the speaker squawker on the front of the body Disconnect the wire from the two speaker terminals of the speaker squawker 1 2 Remo...

Page 17: ... the two speaker terminals 1 2 3 Removing the speaker woofer See Fig 4 and 5 Prior to performing the following procedures remove the front panel Remove the six screws F attaching the sub panel on the back of the front panel Remove the sub panel toward the front 1 2 Removing the sub panel See Fig 6 Remove the four screws G attaching the duct on the upper side of the body Move the duct upwards and p...

Page 18: ...speaker 1 2 Removing the squawker speaker See Fig 2 Prior to performing the following procedure remove the side cover Pull out the saran net toward the front while disengaging the four joints a Remove the two screws C and D respectively Remove the front cover toward the front and disconnect the yellow and black wires from the two tweeter speaker terminals 1 2 3 Removing the front cover See Fig 3 t...

Page 19: ...e front and disconnect the wire yellow and black blue and black from the two speaker terminals 1 2 Removing the woofer speaker See Fig 6 Prior to performing the following procedure remove the side cover and the front cover Remove the two screws F attaching the tweeter speaker on the back of the front cover 1 Removing the tweeter speaker See Fig 7 Fig 5 Fig 6 Fig 7 Woofer speaker E Tweeter speaker ...

Page 20: ...ng and lock lever See Fig 4 By removing the pawl at the section d fixing the return spring dismount the return spring See Fig 4 Remove the three lock levers See Fig 4 10 11 Fig 1 Fig 2 Fig 3 Fig 4 1 Remove the metal cover 2 Remove the CD changer mechanism assembly 3 From bottom side the CD changer mechanism assembly remove the four screws A retaining the CD servo control board 4 Absorb the four so...

Page 21: ... shown in Fig 8 13 14 15 Manually turn the motor pulley in the clockwise direction until the lifter unit stopper is lowered from the section e of CD tray assembly See Fig 8 Pull out all of the three stages of CD tray assembly in the arrow direction f until these stages stop See Fig 6 At the position where the CD tray assembly has stopped pull out the CD tray assembly while pressing the two pawls g...

Page 22: ...mbly in the arrow direction k By raising the CD loading mechanism assembly in the arrow direction l remove the assembly from the lifter unit Fig 10 Fig 12 Fig 11 Fig 13 Removing the CD pick unit See Fig 13 1 2 3 4 Move the cam gear in the arrow direction m Then the CD pickup unit will be moved in the arrow direction n According to the above step shift the CD pickup unit to the center position Whil...

Page 23: ...ly While turning the cam gear q align the Paul r position of the drive unit to the notch position Fig 16 on the cam gear q Pull out the drive unit and cylinder gear See Fig 17 While turning the cam gear q align the Paul s position of the select lever to the notch position Fig 18 on the cam gear q Remove the four screws H retaining the cam unit cam gear q and cams R1 R2 assembly See Fig 18 Cam gear...

Page 24: ...fixing the gear bracket in the arrow direction remove the gear bracket See Fig 18 From the notch u section on the chassis assembly fixing the edge of gear bracket remove and take out the gear bracket See Fig 19 Remove the belts respectively from the right and left actuator motor pulleys and pulley gears See Fig 18 After turning over the chassis assembly remove the actuator motor while spreading th...

Page 25: ... R1 R2 assembly and cam gear q See Fig 22 1 2 3 4 Remove the slit washer fixing the cams R1 and R2 assembly By removing the two pawls w fixing the cam R1 separate R2 from R1 Remove the slit washer fixing the cam gear q Pull out the cam gear q from the C G base assembly Removing the C G base assembly See Fig 22 and 23 Remove the three screws J retaining the C G base assembly Fig 23 Slit washer Pawl...

Page 26: ...en the reversing azimuth screw retaining the playback head 7 Take out the playback head from the front of the head mount 8 The recording and eraser heads should also be removed similarly according to Steps 1 7 above Reassembling the playback recording and eraser heads See Fig 3 1 Reassemble the playback head from the front of the head mount to the position as shown in Fig 3 2 Fix the reversing azi...

Page 27: ...ng the capstan motor assembly See Fig 5 to 7 1 Remove the six screws B retaining capstan motor assembly See Fig 5 2 While raising the capstan motor remove the capstan belts A and B respectively from the motor pulley See Fig 6 Caution 1 Be sure to handle the capstan belts so carefully that these belts will not be stained by grease and other foreign matter Moreover these belts should be hand while r...

Page 28: ...e two slit washers b fixing the capstan shafts R and L and pull out the flywheels R and L respectively from behind the cassette mechanism Removing the reel pulse board and solenoid See Fig 11 1 Remove the five pawls c d e f g retaining the reel pulse P C Board 2 From the surface of the reel pulse P C Board parts remove the two pawls h and i retaining the solenoid Capstan motor Joint bracket Flywhe...

Page 29: ...evice there is no need to adjust this sweeper 4 Since a ceramic oscillator is used there is no need to perform any MPX adjustment 5 Since a fixed coil is used there is no need to adjust the FM tracking 6 The input and output earth systems are separated In case of simultaneously measuring the voltage in both of the input and output systems with an electronic voltmeter for two channels therefore the...

Page 30: ...Cassette mechanism section Back side Cassette Mechanism Unit Section Head azimuth adjusting screw Forward side Head azimuth adjusting screw Reverse side Head azimuth adjusting screw Forward side Head azimuth adjusting screw Reverse side Playback head Playback recording and eraser heads or playback head Tape speed ADJ Bias ADJ L Bias ADJ R ...

Page 31: ...ons Tape recorder section Items Measurement conditions Measurement method Standard values Adjusting positions After setting to the double speed motor confirm that the frequency counter reading becomes 4 800 400 300Hz when the test tape VT712 3kHz has been play back with the playback mechanism When the test tape VT712 3kHz has been played back with the playback mechanism or recording and playback m...

Page 32: ...Measurement output terminal Both recording and headphone terminals Reference frequency 1kHz and 10kHz REF 20dB Test tape TYP AC 225 Measurement input terminal OSC IN AC 225 4 20 A Output deviation between 1kHz and 10kH 1dB 2dB LcH VR101 RcH VR201 LcH VR101 RcH VR201 Electrical performance Items Measurement conditions Measurement method Standard values Adjusting positions 1 While changing over to a...

Page 33: ...e TOC reading finishes Automatic measurement of TE amplitude and automatic tuning of TE balance 500mv div 2ms div Fig 1 Approx 3sec pin 25 of IC601 TE Approx 1 8V VREF Tracking error waveform at TOC reading Power ON Play Key Confirm that the Focus error S cuve signal at the pin28 of IC651 is approx 2Vp p Confirm that the signal from pin24 IC651 is 0V as a accelerated pulse during approx 400ms Conf...

Page 34: ...er diode When the life of the laser diode has expired the following symptoms will appear 1 The level of RF output EFM output ampli tude of eye pattern will below Is the level of RFOUT under 1 25V 0 22Vp p Replace it NO YES O K 3 Semi fixed resistor on the APC PC board The semi fixed resistor on the APC printed circuit board which is attached to the pickup is used to adjust the laser power Since th...

Page 35: ...Block diagram Playback amplifier input R1 R2 I Playback amplifier input NF2 Playback amplifier negative feedback OUT2 Playback amplifier output EQ2 I Equlaizer CTL2 I Pre Amplifier input swithing time constant RIN2 I Recording amplifier input RNF2 I Recording amplifier negative feedback ROUT2 O Recording amplifier output O LC I ALC low cut LPF I ALC low pass filter GND I Vcc Power supply RF I Repp...

Page 36: ...ape B playback recording detect switch Tape B playback detect switch Tape A playback detect switch SPI IN AD port voltage reference VC3 Ready Reset signal input Rolling panel open detection signal input Rolling panel close detection signal input LED Control signal output VOL MS detector signal input Echo ON OFF Not used Echo ON OFF Not used Remote control signal input Tape A mechanism running dete...

Page 37: ...tput LED Control signal output CD LED Control signal output TAPE LED Control signal output TUNER System mute control signal output Tuner supply control Power ON OFF TUNER Chip enable signal output VC3 reset output Power supply O O O O O O O O O O O O O O Pin No Symbol I O Function Pin function 2 2 STROBE DATA CLOCK Q1 Q2 Q3 Q4 Vss Vdd OUTPUT ENABLE Q5 Q6 Q7 Q8 Q s Qs 1 2 3 4 5 6 7 8 16 15 14 13 12...

Page 38: ...al AGC input terminal Capacity connecting terminal for AGC loop filer AGC output terminal Capacity connecting terminal for HPF amplifier 3TENV output terminal Pin No 22 23 24 25 26 27 28 29 30 31 32 Function FE amp reverse input terminal FE amp output terminal GCTL APC terminal FBAL control terminal TBALcontrlo terminal Tracking signal input terminal 1 Tracking signal input terminal 2 Focus signal...

Page 39: ...LPF2 LPF3 ROUT CONTA CONTB CONTC Power supply Microphone mixing input Channel L output Non connect Non connect Channel L input Signal bias Connect to GND Channel R input Connects to LPF time constant element Connects to LPF time constant element LPF outpout Channel R output Mode select input A Mode select input B Mode select input C I O I I I O O O O I I I Pin No Symbol I O Description 2 Pin funct...

Page 40: ...ADLPF IN ADLPF OUT ADINT OUT ADINT IN VCC NC2 MUTE CR Connect GND Echo level control Non connect Analog part DC bias DA side integrator input DA side integrator output DA side LPF input DAside LPF output Mix AMP output for original tone echo tone Mix AMP input pin for original tone AD side LPF input AD side LPF output AD side integrator output AD side integrator input Power supply Non connect Mute...

Page 41: ... 27 28 29 30 OSC BUFFER AM OSC REG AM RF AFC AM AGC O I O I I I AM Local oscillation Signal output This is a terminal of AM Local oscillation circuit Register value between pin 26 and pin28 desides the frequency width of the input signal AM RF signal input This is an output terminal of voltage for FM AFC This is an AGC voltage input terminal for AM O O I O AM detection output FM detection output M...

Page 42: ...ll BTL amplifier outputs ON OFF BTL AMP 1 input pin BTL AMP 1 input pin For gain adjustment BTL AMP 1 input pin Non inverting side BTL AMP 1 input pin Inverting side BTL AMP 2 input pin Inverting side BTL AMP 2 input pin Non inverting side BTL AMP 2 input pin For gain adjustment BTL AMP 2 input pin External transistor collector PNP connection 5V power supply output External transistor PNP base con...

Page 43: ...e power on reset Input output port Input output port Data input output Function IF counter signal input IF signal output Not use AM Local OSC signal output FM Local OSC signal input Power suplly VDD 4 5 5 5V When power ON Reset circuit move PLL charge pump output H Local OSC frequency Height than Reference frequency L Low Agreement Height impedance Input for active lowpassfilter of PLL Output for ...

Page 44: ... TR1 TR3 TR2 TR4 TR5 TR6 TR8 R8 C2 TR14 TR15 TR16 R14 R11 R13 R12 R10 R9 TR9 TR10 TR12 TR13 TR11 TR7 C1 D1 R6 R3 R4 R5 R7 13 11 14 15 9 8 12 5 6 7 10 2 R2 SUB STK402 050 MX GT98 95V STK402 030 MX GT88 85V MX G78 75V IC601 Power amp 1 Pin layout 2 Block diagram 1 15 ...

Page 45: ...TR7 R7 TR9 TR10 TR8 TR20 R13 R16 R19 TR18 R14 R15 R16 TR17 R17 D12 TR12 TR11 C11 C12 R11 TR14 TR13 TR15 R12 TR41 R41 D41 D51 TR32 R31 Comparator Comparator D53 D52 D42 D43 SUB 1 3 2 7 5 4 6 12 9 8 11 10 18 13 17 14 15 16 STK412 010 MX GT98V GT95V STK412 000 MX GT88V GT85V STK412 090 MX G78V G75V IC701 Power amp ...

Page 46: ...E L INL MUXOUT VOLUME VOLUME TREBLE TREBLE MIDLE MIDLE SPEAKER ATT RIGHT SPEAKER ATT LEFT BASS BASS SUPPLY G G I C BUS DECODER LATCHES 2 0 30dB 2dB STEP INPUT MULTIPLEXER GAIN CSL DIG GND TREBLE R TREBLE L MIN L MOUT L BOUT L BIN L BOUT R BIN R MOUT R MIN R INR MUXOUTR INL SDA CRE Vs AGND ROUT LOUT R IN4 R IN3 R IN2 R IN1 L IN1 L IN2 L IN3 L IN4 MUXOUTL TDA7439 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ...

Page 47: ...er supply terminal Output selection control terminal Output selection control terminal Output selection control terminal Output selection control terminal Non connect Non connect Connected to GND upon normal use Multi plexor output terminal Connect to GND I O O O O O No Symbol I O Function 2 Pin Function 1 Block Diagrams BA3835S MX GT98 95V IC812 SPI B P F 1 2 3 4 5 6 7 8 9 18 17 16 15 14 13 12 11...

Page 48: ...Layout 1 2 3 4 5 16 17 18 Vss DATA CLOCK LCK Q0 Q11 OE VDD I I I O I GND Serial Data input Shift Clock of Data Rise Edge Trigger Latch Clock of Data Rise Edge Trigger Parallel Data Output Nch Open Drain FET Output Enable Output FET H Level is OFF Power Supply Pin No Symbol I O Function Latch Data L H OUTPUT ON OFF 2 Pin Function BU2092 F IC811 Port expander BA3126N IC301 R P switch R E C S W G 1 2...

Page 49: ...1 VCC2 P2 OUT2 Input Output Mode IN1 IN2 OUT1 OUT2 Brake 0 0 0 0 1 0 1 0 0 1 0 1 1 1 0 0 CLOCKWISE COUNTER CLOCKWISE Brake LB1641 IC851 IC852 DC motor driver 1 Pin layout 2 Pin function 1 2 3 4 5 6 7 8 1 A OUTPUT 2 A INPUT 3 A INPUT 4 V 5 B INPUT 6 B INPUT 7 B OUTPUT 8 V NJM4580L US ver only IC901 Mic amp ...

Page 50: ...COMPANY OF JAPAN LIMITED AUDIO COMMUNICATION BUSINESS DIVISION PERSONAL MOBILE NETWORK BUSINESS UNIT 10 1 1chome Ohwatari machi Maebashi city 371 8543 Japan No 21026 MX GT98V MX GT95V MX GT88V MX GT85V MX G78V MX G75V ...

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JVC MX-G75V, Service Manual, Page: 45 / 50

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