Jvc KDV 400 Service Manual

Page 1

.JVB

SERVICE MANUAL

MODEL KD'V4OO A/B/C/E/ED/J/U/NA

NB/NC/NE/NJ/NED

Contents

Page Page

Safety Precautions ................................................. 2 Integrated Circuit ................................................... 15
Features .............................................................. 3 Wiring Connections ................................................ 16
Specifications ....................................................... 3 P.C. Board Parts and Parts List
Names of Control and Their Functions ....................... 4 LCD P.C. Board ................................................ 1 7
Location of Main Parts ............................................ 5 DOLBY NR P.C. Board ......................................... 17
Removing the Main Parts ........................................ 6 Main P.C. Board ................................................. 18
Main Adjustments ................................................. 8 Exploded View of Mechanism Assembly .................... 20
Block Diagram ....................................................... 12 Mechanism Assembly Parts List ............................ 21
Standard Schematic Diagram of KD-V4OO Exploded View of Enclosure Assembly ....................... 22

(Amplifier Circuit) ................................................ 1 3 Enclosure Assembly Parts List ............................... 23
Standard Schematic Diagram of KD-V400 Packing and Packing Parts List ................................. 25

(Mechanism Control Circuit) .................................. 14 Accessories .............................................. Back Cover
Standard Schematic Diagram of KD-V4OO

(L.C.D Circuit) ..................................................... 15

No.4238

July 1984

Page 2

2

Safety Precautions

1. The design of this product contains special hardware.

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. Service should be per-
formed by qualified personnel only.

.Alterations of the design or circuitry of the product

should not be made. Any design alterations or additions
will void the manufacturer's warranty and will further
relieve the manufacturer of responsibility for personal in-
jury or property damage resulting therefrom.

. Many electrical and mechanical parts in the product

have special safety-related characteristics. These
characteristics are often not evident from visual inspec-
tion nor can the protection afforded by then 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 ( A ) on the
schematics and parts list in Service manual. The use of a
substitute replacement which does not have the same
safety characteristics as the recommended replacement
part shown in the parts list in Service manual may create
shock, fire, or other hazards.

. The leads in the products are routed and dressed with

ties, clamps, tubings, barriers and/or the like to be
separated from live parts, high temperature part, mov-
ing parts and/or sharp edges for the prevention of elec-
tric shock and fire hazard.

When service is required, the original lead routing and
dress should be observed, and they should be confirmed
to be returned to normal, after re-assembling.

. Leakage current check

(Safety for electrical shock hazard)

After re-assembling the product, always perform an
isolation check on the exposed metal parts of the Pro-
ducts (antenna terminals, knobs, metal cabinet, screw
heads, earphone jack, control shafts, etc.) to be sure the
product is safe to operate without danger of electrical
shock.

(No.4238l

Do not use a line isolation transformer during this check.

0 Plug the AC line cord directly into the AC outlet. Us-
ing a Leakage Current Tester", measure the leakage
current from each exposed metal part of the cabinet,
particularly any exposed metal part having a return
path to the chassis, to a known good earth ground
(water pipe, etc.). Any leakage current must not ex-
ceed 0.5 mA AC lr.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
1500 (2 10 W resistor paralleled by a 0.15 uF AC-
type capacitor between an exposed metal part and a
known good earth ground (water pipe, etc.).
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. Any
voltage measured must not exceed 0.75 V AC
(r.m.s).
This corresponds to 0.5 mA AC (r.m.s).

AC VOLTMETER
(HAVING 1000 ("l/V,
OR MORE SENSITIVITY)

CD

---0 O

0.15 #F AC-TYPE

Will D.

1500 Q 10 W PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

GOOD EARTH GROUND