Jvc PCW 300 LB Service Manual

Page 1

JVC
SERVICE MANUAL

MODEL PC-WSOO L/LB/LD

Contents

Safety Precautions ..
Features
Specifications ...........................................
Names of Controls and Connection Terminals .
Various Usages ...........
Location of Main Parts ..
Removal of Main Parts ..
Main Adjustments
How to Engage Dial Cord

Block Diagram ................ ..
Integrated Circuit ................................................... 19
Standard Schematic Diagram of PC-W300L/LB

(Tuner Circuit) ..................................................... 20
Standard Schematic Diagram of PC-WSOOLD

(Tuner Circuit) .................................................... 21
Standard Schematic Diagram of PC»W300

(Amplifier Circuit) ................................................ 22

Wiring Connections ...........................
P.C. Board Parts (Amplifier P.C. Board) .
Amplifier P.C. Board Parts List .
Tuner P.C. Board Parts List ......
DIN/Power Supply P.C. Board Parts List
P.C. Board Parts of Tuner/PowerlDlN ........

Enclosure Assembly Parts and Electrical Parts ........... 32
Enclosure Assembly Parts and Electrical Parts List
Mechanical Component Parts List ........................ 36
Comparison Table Between A mecha. and B mecha. . 38

Mechanical Component Parts .................................. 39

Exploded View, Connection Figure and Parts List

for Speaker .........

Connection Figure .
Packing. Packing Parts Is .
Accessories ....................

No. 1542
February 1984

Page 2

PC

2

Safety Precautions

l. 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.

2. Alterations of the design or circuitry of the product

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

3. 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 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 ( 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.

4. 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.

Power switch A'ssy

V. select switch
AC IN jack
DC jack

Fuse

DIN P.C. Board Ass'y

Power supply P.C. Board Assv
Power transformer

(N0. 1542)

5. 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.

Do not use a line isolation transformer during this check.

I 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.l. Any leakage current must not ex-
ceed 0.5 mA AC (r.m.s.l.

O 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 [LF 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
CD (HAVING 1000 mv.

OR MORE SENSITIVITY)
-o o~

0.15 itF ACVTYPE

*l i-
D
1500 [Z 10 W PLACE THIS PROBE
ON EACH EXPOSED

GOOD EARTH GROUND METAL PART