Jvc RX 715 VTN Service Manual

Page 1

RX-715VTN

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SERVICEMANUAL

RX-715VTN

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Contents
Safety Precautions ....................... 1-2 Disassembly Procedures ................. 1-45
Instruction Book Adjustment Procedures ................. 1-46
Description of Major ICs ................ 1-32 Block Diagrams ......................... 1-48
Internal Block Diagram Printed Circuit Boards ................... 1-50

of the Other ICs ........... 1-41 Schematic Diagrams ................ Insertion
Internal Connection of the FL Display 1-43 Parts List ........................... 2-1

No. 20463
JAN.. 1994

Page 2

http: //getMANUAL . com
RX-715VTN

1-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

Measure the AC voltage across the resistor a (Having 1000
With the AC voltmeter. ohms/volts, . . _
Move the resistor connection to each exposed 3 °_ 0' "W9 sens'tlv'ty)
metal part, particularly any exposed metal part
having a return path to the chassis, and 9,15,; Ac Type
meausre the AC voltage across the resistor. -||-
Now, reverse the plug in the AC outlet and 9
repeat each measurement. Any voltage "vv nggkeeggosed
measured must not exceed 0.75VAC (r.m.s.). 15°0010W 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.

1-2 (No. 20463)

Page 4

RX-71 5VTN

Switches and Controls

1-4 (No. 20463)

Familiarize yourself with the main switches and controls on your JVC RX-715VTN receiver.

M Rx my mm

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Receiver

m SURROUNDnmmmm
Display window

Bi RECEIVED/STANDBY indicator
m REMOTE SENSOR window
{E MASTER VOLUME control
E SOURCE SELECT buttons

'1]. TUNER buttons

Bi] PHONES jack

[9.] SPEAKERS buttons

10 TREBLE control

[E] BASS control

72 BALANCE control

TE CHARACTER buttons

[E SURROUND processor buttons
[5;] LOUDNESS switch

E POWER switch

Turns power On or Stand by

Remote Control

B

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POWER switch

Turns power On the RX<715VTN or Stand by

SOURCE SELECT buttons
Buttons for operating components
CONTROL buttons
SURROUND processor buttons
FADE MUTE button

SLEEP button

VOLUME button

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Page 7

RX-71 5VTN

COMPU LINK-3 COMPU LINK-3 SYNCHRO jacks on the back of the receiver connect the COMPU LINK

Connections remote control system. This system connects other JVC audio components with the receiver
to make listening and recording more convenient. To use this system, attach the cables provided
with yourJVC components to the COMPU LIN K-3 SYNCHROjacks on the rear panel of each
component. Then connect the cables to the receiver

NOTES:

0 COMPU LINK-3 is an upgraded version of COMPU LINK -l. lfyour equipment
provides COMPU LINK-1 jacks, you can still connect your equipment, but slight
imperfections may result Automatic Power ON/OFF, for example, may not always
function properly.

' Refer to page 24 for details about the COMPU LINK remote control system.

A CAUTION! Do not connect Tape Deck 2 to the COMPU LINK jacks. It may
cause the COMPU LINK system to malfunction

CD PLAYEH TAPEDECKi

TURNTABLE

Other Audio Use the socket on the back of the receiver to connect the power supply of any audio components.
canneuions By pressing the POWER switch on the remote control, you can tum the receiver, and all
connected components, on or off at the same time.
AC OUTLETS
swrrcuED . ,
itc12w~sonz In the United States, AC outlets have a capacity of 180 watts

TOTALMAX180W/15A

m IE A CAUTION! Do not connect any components that consume more power than the
capacity of the AC outlet. This capacity is indicated above the socket on the back of

the receiver.

P
age 6 (No. 20463) 1-7

Page 16

RX<715VTN

Receiving an AM/FM Broadcast

FREouEwcv

Manual Tuning

Automatic Tuning

1-16 (NO. 20463)

To receive an AM/FM broadcast, select either AM or FM using the AM button or FM button.
Then tune to the precise frequency using the FREQUENCY buttons.

Tuning

Tune to the frequency of a desired station using the FREQUENCY buttons. Pressing the right
button increases the frequency, and pressing the left button decreases the frequency. Tapping
the FREQUENCY button once changes the frequency in steps of 10 kHz for AM and 0,] MHz
for FM.

There are two tuning modes: Manual and Automatic.

lfyou know the frequency ofa desired station, hold down the FREQUENCY button to start the
frequency changin g quickly. Release the FREQUENCY button nearthe desired station and tap
it repeatedly until you arrive at the correct frequency.

lfyou want to scan frequencies for a desired station, hold down the FREQUENCY button to
start the frequency changing quickly. When you release the FREQUENCY button, the
frequency continues to change until it reaches a station

When a station is correctly tuned, the TUNED" light appears on the display window.

Once a tuned frequency is preset, it can be directly recalled using the TUNER buttons. For
details, see pages 16717.

NOTE: When you use automatic tuning, weak stations are ignored. T0 pitk up weak
stations, use manual tuning.

IMPORTANT! If the receiver is tuned to a station but the TUNED" light does not
appear, try rotating the antenna for better reception,

Selecting an FM Reception Mode

Pressing the FM MODE/MUTE switch switches between these modes

The MUTE-AUTO" light appears in the display window. You hear either stereo sound or
monaural sound, depending on the broadcast. If it is a stereo broadcast, the STEREO" light
appears, This mode is also useful for suppressing static noise" between stations.

The MUTE-AUTO" light disappears. You hear monaural sound even if a broadcast is in
stereo. This mode is also useful when a stereo broadcast is noisy because of a weak signal.

NOTE: Using the Automatic Tuning mode, the sound ()fa broadcast with a weak Signal
may be muted. In this case, select the monaural mode.

Page 15