Jvc RX 9 VBK Service Manual

Page 1

FiX-QVBK

JVB

_ SERVICE MANUAL

MOBET. NO. RXQVBK

Contents

Safety Precautions ....................... 1-2
Instruction Book ......... Separate-Voiume insertion
Block Diagram .......................... l~3
Technical Expianations .................... 1-5
Removal Procedures ...................... 179

Adjustment Procedurés
(i) FM/AM Tuner RC. Beard
(2) Power AmplifIEf P.C. Board .
Functions 0? It: on the PrerAmpiifier PC Board . . , . 1:12
Handling Precautions of LCD Paneis ............ 1-12
Servicing Method for AWG #20 Wires

with Ciamping Tsiminais ................. 1-13

incemal Biuck Diagrams of Maior {Cs ........... HA
Parts List .............. Seoarate«Volume Insertion
Connection Diagrams .................. Insertion
Schematic Diagrams

(1) Tuner Section .................... insertion
(2) Logic Section ..................... Insertion
(3) Pre-Ampiifier Section ............... insertion
(4) Power Amplifier Section ............. Insertion
(5) Sub Cnntroi Semion . . . . . . i z ........ insertion
(6) When 0301 ~0304 are used as subsiituxes . Insertion
(7i Buffer PC Board Section ................ i-23

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RXAQVBK J

Safety Precautions

1. The design of this product contains special hardware,

many circuits and components specially for safety pur
poses.
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
peri orrned by qualified personnel only.

2. Alterations ol the design or circuitry of the product
should not be made. Any design alterations or additions
will void the manufacturers warranty and will iurther
relieve the manufacturer of responsibility for personal
injury or property damage resulting therefrom.

3. Many electrical and mechanical parts in the product
have special safelyrelated characteristics. These charac-
teristics 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, eta. 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 l A l on the parts list in Service
manual, The use of a substitute replacement which does
not have the same safety characteristics as the recom-
mended 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 irom live parts, high temperature parts, mov»
ing 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 they should be confirmed
to be returned to normal, after rerasscmbiing.

CHECKING YOUR LINE VOLTAGE (Except for U,S.A., Canada, Australia, U.K.and Continental Europe.)
Before inserting the power plug, please check this setting to see that it corresponds with the line voltage in
your area. If it doesn't, he sure to adjust the voltage selector switch to the proper setting before operating this
equipment, The voltage selector switch is located on the rear panel.

i»21N0.2912)

5. Leakage current check

[Safety for electrical shock hazard)

After rc-assembling the product, always perform an

isolation check on the exposed metal parts of the

Products lantanna 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 part 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 0.5 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 Q 10 W resistor paralleled by a 0,15 pF AC-
type capacitor between an exposed metal part anda
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. Any
voltage measured must not exceed 0.75 V AC (r.m.s.l,
This corresponds to 0.5 mA AC lr,m.s.).

AC V 0 LTM ETE R
(Having 1000 ohms/volt.
or more sensitivity )

(1|er AC was

Place this probe

ii» on each exposed
/ 1500!: MM mela| part.

l

Good Earth G round

CAUTION Before selecting the Voltage selector switch to proper voltage disconnect the power plug.