Jvc MXJ 750 R Service Manual

Page 1

NIX-J700
MX-J750R

JVE:
SERVICE MANUAL

MX-J700
MX-J750R

Area Suffix
SP-MXJ700 CA-MXJ7OO sp-mxnoo J ------------------- U.S.A.
_ C Canada
6 B --------------------- UK.
© 7 __ _ @ E ------ Continental Europe
_ 5 , '33 EN ------- Northem Europe
' L ' 5) EV -------- Eastern Europe
U ------------- Other Areas

l--- ---l US ------- Sin a ore
J-ii W l * i ux --------- Saudigteria
This Illustration is MX-J700 UY -------------- Argentina
@ COMPACT R D 5
USE @ ale/NI
"5 9'0 Only MX-J750R(B/E/EN/EV)
Each difference point
Model CD/DECK/RECEIVER SPEAKER RDS MIC Digital output Packing method
MX-J700(J/C) CA-MXJ700 SP-MXJ700 - - 0 together
MX-J700(U/US/UX/UY) CA-MXJ700 SP-MXJ7OO - O - another
MX-J750Ft(B/E/EN/EV) CA-MXJ75OFt SP-MXJ750R O - 0 another
Contents
Safety precautions ----------------------- 1-2 Flow of functional operation
Important for laser products ------------ 1-3 until TOC read ------------ 2-28
Preventing static electricity ------------- 1-4 Maintenance of laser pickup 2-29
Precautions at disassembling Replacement of laser pickup ------------ 2-29
and parts replacement ------- 1-5 Description of major ICs ----------------- 2-30
InstructionS(CA-MXJ750R) ------------------- 1 -6~14 Block diagrams ----------------------------- 2-49
Instruction3(sp-Mx0750R) 1-15~16 Standard schematic diagrams ---------- 2-51
Disassembly method ------- 2-1 Printed circuit boards -------------------- 2-60~64
Adjustment method ----------------------- 2-23 Parts list -------------------------------------- 3-1~33
Diagnosis which uses
extension wire method --------- 2-27
This service manual is made from 100% recycled paper. N 0.20821

COPYRIGHT 2000 VICTOR COMPANY OF JAPAN, LTD.
© Mar. 2000

Page 2

MX-J700 l

MX-J750R_l

-Safety Precautions

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. Sen/ices 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 manufacturers
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 (A) 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~assemb|ing 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.

0 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 1,5009 10W resistor paralleled by
a 0.15uF AC-type capacitor between an exposed

metal part and a known good earth ground. féfiflgggm
Measure the AC voltage across the resistor with the 7 ohms/volts,

AC voltmeter. or more sensitivity)
Move the resistor connection to each exposed metal °

part, particularly any exposed metal part having a 0.15uF AC TYPE

return path to the chassts, and measure the AC _"_ Placethis
voltage across the resrstor. Now, reverse the plug in probe on
the AC outlet and repeat each measurement. Voltage WV each exposed
measured any must not exceed 0.75 V AC (r.m.s.). 15009 10W metal part.

This corresponds to 0.5 mA AC (r.m.s.).
Good earth ground

- Warning

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.

A CAUTION Burrs formed during molding may be left over on some parts of the chassis. Therefore,
pay attention to such burrs in the case of prefomiing repair of this system.
1-2

Page 25

lRemoving the rear cover] rear panel
(See Fig.23 to 26)

- Prior to performing the following procedure, remove
the metal cover and the CD changer mechanism
assembly.

XThere is no need to remove the front panel
assembly.

1. Remove the two screws V attaching the rear cover
on the back of the body.

2. Remove the five screws E & F, F' attaching Aux,
MAIN speaker and sub speaker board to the rear
panel on the back of the body.

3. Remove the screw E' attaching the digital output
terminal.
(Only digital output is installed model.)

4, Remove the five screws W attaching the heat sink,
voltage selector and the preamplifier board to the
rear panel on the back of the body.

5. Remove the two screws W' attaching the voltage
selector to the rear panel on the back of the body.
(Only ver. U, US, UX, UY)

6. Remove the screw X attaching the rear panel to the
base chassis on the back of the body.

7. Release the two joints i and j on the rear panel
bottom using a screwdriver, and detach the rear
panel backward.

Remove the tuner board in case of necessity (Refer
to Fig.21).

MX-J700/MX-J750R

Rear panel

Rear cover

Fig.23

Heat sink

||l|||llllllllllllllllufllllll

llllllllllllllllllmlllllllll
. . .

Rear panel

Joint i

Fig.25

2-9

Page 34

MX-J700/ M X-J750R

l Removing the actuator motor and belt
(See Fig.18~21)

Gear bracket

1, Remove the two screws K retaining the gear bracket -.-J
(See Fig.19). ° fie GK 0 i
2, While pressing the pawl "t" fixing the gear bracket in the 3 <9 I ,7
arrow direction, remove the gear bracket / \ l @
(See Fig.19). & Pulley gear
3. From the notch "u section" on the chassis assembly 0 (9° Belt
fixing the edge of gear bracket, remove and take out the M ll
gear bracket(See Fig. 20). ° ; (C) D K 0 or W ey
4. Remove the belts respectively from the right and left °
actuator motor pulleys and pulley gears(See Fig. 19). e: "LG 0 i K
5. After turning over the chassis assembly, remove the a 0 Q
actuator motor while spreading the four pawls "v" lixing ,
the right and left actuator motors in the arrow 1.:l': j;
direction(See Fig. 21). Pawl 1
[Note] When the'chassis assembly is turned over under puney gear Belt /
the conditions wherein the gear bracket and belt K
have been removed, then the pulley gear as well MOW pulley
as the gear, etc. constituting the gear unit can Fl 18
possibly be separated to pieces. In such a case, 9.
assemble these parts by referring to the assembly
and configuration diagram in Fig. 22. Actuator motor
Chassis assembly 0 ,7 7 »- -
o n f L. e O LY 0
O O
V 7' 9 ® "
Gear bracket / (3
§ m) V
'7:- '
L F O , is:
We /
Fig.19 Fig.20
Assembly and Configuration Diagram
Pulley gear

Cylinder gear

Select gear Gross gear U
Gross gear L Gear C

Fig.21

2-18