This is the 65 pages manual for Jvc MXGT 98 V Service Manual. Read or download the pdf for free.
If you want to contribute, please mail your pdfs to info@audioservicemanuals.com.
Page: 1 / 65
Extracted text from Jvc MXGT 98 V Service Manual (Ocr-read)
Page 1
MX-GT98V/MX-GT95V/MX-GT88V
MX-GT85V/MX-G78V/MX-G75V
1-2
1. This design of this product contains special hardware and many circuits and components specially for safety
purposes. For continued protection, no changes should be made to the original design unless authorized in
writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services
should be performed by qualified personnel only.
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the product
should not be made. Any design alterations or additions will void the manufacturer's warranty and will further
relieve the manufacture of responsibility for personal injury or property damage resulting therefrom.
3. Many electrical and mechanical parts in the products have special safety-related characteristics. These
characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily
be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which
have these special safety characteristics are identified in the Parts List of Service Manual. Electrical
components having such features are identified by shading on the schematics and by ( ) on the Parts List in
the Service Manual. The use of a substitute replacement which does not have the same safety characteristics
as the recommended replacement parts shown in the Parts List of Service Manual may create shock, fire, or
other hazards.
4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be
separated from live parts, high temperature parts, moving parts and/or sharp edges for the prevention of
electric shock and fire hazard. When service is required, the original lead routing and dress should be
observed, and it should be confirmed that they have been returned to normal, after re-assembling.
5. Leakage current check (Electrical shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metal parts of the product
(antenna terminals, 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 having a return
path to the chassis, to a known good earth ground. Any leakage current must not exceed 0.5mA AC (r.m.s.).
Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more
sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15 F AC-type capacitor
between an exposed metal part and a known good earth ground.
Measure the AC voltage across the resistor with the AC
voltmeter.
Move the resistor connection to each exposed metal part,
particularly any exposed metal part having a return path to
the chassis, and measure the AC voltage across the resistor.
Now, reverse the plug in the AC outlet and repeat each
measurement. Voltage measured any must not exceed 0.75 V
AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.).
1. This equipment has been designed and manufactured to meet international safety standards.
2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
3. Repairs must be made in accordance with the relevant safety standards.
4. It is essential that safety critical components are replaced by approved parts.
5. If mains voltage selector is provided, check setting for local voltage.
Good earth groundPlace this
probe on
each exposed
metal part. AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500 10W
0.15 F AC TYPE
!
Burrs formed during molding may
be left over on some parts of the
chassis. Therefore, pay attention to
such burrs in the case of
preforming repair of this system.
In regard with component parts appearing on the silk-screen printed side (parts side) of the PWB diagrams, the
parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the " "
mark nearby are critical for safety.
When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer.
(Except the J&C version)
Page 2
MX-GT98V/MX-GT95V/MX-GT88V
MX-GT85V/MX-G78V/MX-G75V
1-3
Important for laser products
1.CLASS 1 LASER PRODUCT
2.DANGER : Invisible laser radiation when open and inter
lock failed or defeated. Avoid direct exposure to beam.
3.CAUTION : There are no serviceable parts inside the
Laser Unit. Do not disassemble the Laser Unit. Replace
the complete Laser Unit if it malfunctions.
4.CAUTION : The compact disc player uses invisible laser
radiation and is equipped with safety switches which
prevent emission of radiation when the drawer is open and
the safety interlocks have failed or are defeated. It is
dangerous to defeat the safety switches.5.CAUTION : If safety switches malfunction, the laser is able
to function.
6.CAUTION : Use of controls, adjustments or performance of
procedures other than those specified herein may result in
hazardous radiation exposure.
VARNING : 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 utsettelse
for stråling.
Position of labels
WARNING LABEL
!CAUTIONPlease use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.
DANGER : Invisibie laser radiation
when open and interlock or
defeated.
AVOID DIRECT EXPOSURE TO
BEAM (e) VARNING : Osynlig laserstrålning
är denna del är öppnad och spårren
är
urkopplad. Betrakta ej strålen.
(s)
VARO : Avattaessa ja suojalukitus
ohitettaessa olet alttiina
näkymättömälle lasersäteilylle.Älä
katso säteeseen. (d) ADVARSEL :Usynlig laserstråling
ved åbning , når
sikkerhedsafbrydere er ude af
funktion. Undgå udsættelse for
stråling. (f)
CLASS 1
LASER PRODUCT
CLASS 1
LASER PRODUCT
Page 31
MX-GT98V/MX-GT95V/MX-GT88V
MX-GT85V/MX-G78V/MX-G75V
1-32
Items Measurement
conditionsMeasurement methodStandard
valuesAdjusting
positions
1.With the recording and playback mechanism,
load the test tapes(AC-225 to TYP ),and set the
mechanism to the recording and
pausing conditions in advance.
2.After connecting 100 in series to the recorder
head,measure the bias current with a valve
voltmeter at both of the terminals.
3.After resetting the [PAUSE] mode,start recording.
At this time,adjust VR101 for LcH and VR201 for
RcH so that the recording bias current values
become 4.0 A (TYP ).
1.With the recording and playback mechanism,load
the test tape(AC-225 to TYP ),and set the
mechanism to the recording and pausing condition
in advance.
2.While repetitively inputting the reference frequency
signal of 1kHz and 10kHz from OSC IN, record and
playback the test tape.
3.While recording and playing back the test tape in
TYP ,adjust VR101 for LcH and VR201 for RcH
so that the output deviation between 1kHz and
10kHz becomes -1dB 2dB. Adjustment of
recording bias
current
(Reference
value)
Adjustment of
recording and
playback
frequency
characteristics*Mode : Forward or
reverse mode
*Recording mode
*Test tape
: AC-225
Measurement output
terminal
:Both recording and
headphone terminals
Reference frequency
:1kHz and 10kHz
(REF:-20dB)
Test tape
:TYP AC-225
Measurement input
terminal
:OSC INAC-225
:4.20 A
Output
deviation
between
1kHz and
10kH
:-1dB 2dBLcH
:VR101
RcH
:VR201
LcH
:VR101
RcH
:VR201
Electrical performance
Items Measurement
conditionsMeasurement methodStandard
valuesAdjusting
positions
1.While changing over to and from BIAS 1 and 2,
confirm that the frequency is changed.
2.With the recording and playback mechanism.
load the test tape (AC-225 to TYP ),and set the
mechanism to the recording and pausing
conditions in advance.
3.Confirm that the BIAS TP frequency on the
P.C.board is 100kHz 6kHz.
1.With the recording and playback mechanism,
load the test tapes(AC-225 to TYP ),and set the
mechanism to the recording and pausing condition
in advance.
2.After setting to the recording conditions,connect
1M in series to the eraser head on the recording
and playback mechanism side,and measure the
eraser current from both of the eraser terminal. Recording
bias frequency
Eraser current
(Reference
value)*Recording and
playback side forward
or reverse
*Test tape
:TYP AC-225
*Measurement
terminal BIAS TP on
P.C.board
*Recording and
playback side forward
or reverse
*Recording mode
*Test tape
:AC-225
Measurement terminal
Both of the eraser
head100kHz
+9kHz
-7kHz
TYP
:75mA
Reference values for electrical function confirmation items
Page 49
200109(V)
VICTOR 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