Jvc XTMXS 4 BK Service Manual

Page 1

CA-MXS4BK

(Unit No. XT-MXS4BK)

JVI: cmmscmvai

A WW B
u ..
© 9-9
ed Sec- <3;g© g©u E
\__l \_l

* For instruction manual, packing materials and accessories, please refer to the

RX-MXS 43K (SM. No.20404).

* RX-MXS 4BK is needed ( for power supply etc.) when servicing.

Contents

Safety Precautions
Important for Laser Products -
Description of Major LSls
Internal Block Diagrams of Other le -
Internal Connection of FL Display Tube

1-11

Disassembly Procedures 1 - 12
Adjustment Procedures -------------------------------- 1 -16
Maintenance of Laser Pickup ------------------------ 1 -20

Flow of Functional Operation

Until TOC is Read
Replacement of Laser Pickup -
Troubleshooting
Application Points for Greasae --------------------
Schemaiic Diagrams
Block Diagrams
Printed Circuit Boards
Parts Lisl

COPYRIGHT © 1993 VICTOR COMPANY OF JAPAN, LTDI

HflfiElE

DIGITAL AUDIO

No. 20405
Mar. 1993

Page 2

XT-MXS4BK

-Safety Precautions

1. The 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 (A) on the Parts
List in the Service Manual. The use of a substitute repalcement 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 currnet 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,
contorl 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.).

0 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 1,5000 10 W
resistor paralleled by a 0.15 ,uF AC-type capacitor between an exposed metal part and a
known good earth ground.

AC VOLTMETER

kw

Measure the AC voltage across the resistor ,
with the AC voltmeter. E 513433011?
Move the resistor connection to each exposed o o_ 0' morese"5it'VY-i
metal part, particularly any exposed metal part
having a return path to the chassis, and 0.15,A= ACTYPE
meausre the AC voltage across the resistor. -||-
Now, reverse the plug in the AC outlet and P'af this
repeat each measurement. Any voltage #r >ggéheefigosed
measured must not exceed 0.75VAC (r.m.s.). 15°0910W metal part.
This corresponds to 0.5 mA AC (r.m.s.). Good earth 9mm:

-Warnmg

. This equipment has been designed and manufactured to meet international safety standards.

. It is the legal responsibility of the repairer to ensure that these safety standards are
maintained.

. Repairs must be made in accordance with the relevant safety standards.
. It is essential that safety critical components are replaced by approved parts.
. If mains voltage selector is provided, check setting for local voltage.

1-2 (No. 20405)

Page 22

XT-MXS4B K

Troubleshooting

PDWEY on

l

Does the FL
indication
light
correctly?

YES

Does the disc
tray be moved
in and out using
OPEN I CLOSE
button?

YES

Does the
indications on

NO

The following shows the status of the various circuits from
turning on the power to start of disc play .

I See front 1I

-'>I Clrcu1tsectlon.JI

I See loadIng i

iL circuit sectlon. JI

l'
I See feed servo I
IL circuit section. .l

' "" ll

the FL display N0
show---when
the disc tray is
clased?
YES
Can it read N0 Does the disc N0
1'0ch rotate?
'm-S-ee tracking 1 YES YES
I servo circuit I
I ct n I
-33-? ______ -l _ Is the tracking loop
I See feed servo INO Can It play the applied?
| CIrwIt sectIon. 1'6- first track?
I See spindle I YES YES TP6(TE)
I servo circuit I 0V
I .
L__SSEU_OE _____ .I
Can a IV/dlv..
asset/div
waveformbe
---------- '1
rSee tracking I menu?
I servo circuit : 0
.section I NO Can it search to
__________ 44-- each track _____ ___-_
I See feed servo : correctly? I See tracking 1
I circuit section I I servo circuit I
'- ---------- - YES 'I section 1'
, . . Does the RF
To audIo cIrcuIt No Does it sound signal come at YES
section. 0K? TP8when the
YES disc is rotated?

Check general
operations.

VINC

check the RF
circuit and
pickup.

ILsection.

1-22 (No. 20405)

.I

Are all operation
keys on the
front panel and
the FL display
correct?

YES

OK

Adjust the PLL I
free- running I
frequency.

{heck theAuto I

IDoes the pickup
ens move u .
and down mater NO '5 p"5 °f
the disc tray is P802 0V7
closed? YES
YES
I'_S_Iee_f5cu§ 'sén'rS I
Does the laser I circuit section. I
lightf or """""""" "
approximately 8
seconds afterthe in37 of
raISy NO [(2 51 V f
closed?(CheCk the appro: 5am No
laserly power after closing the
meter) disc tray?
ES YES
Check the
pickup and the
connections
with P801 and
the pickup,
r """ - ----- 1
See spIndIe
I . -
I servo cichIt : figgfififfflftfi"
' sectwn- ' |C951 and P801.

I See focus servo I
I circuit section. J