Jvc DC ME3 Service Manual

Page 1

DCME3

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Contents

Safety Preceution -----------------

Important for Lazar Products -

Instruction Book -------------------------------------------------- 1-4

CA-ME3

Description of Major ICS ....................................... 2_1

Disassembly Procedures --------------------------------------- 2-9

Adjustmem Procedures --------------------------------------- 2715

@EWS'AIE

DIG ITAL AU DIO

snack Diagram ...............

Ic Tarminel voltage chart
Schematic Diagrams ............................................. 2-25
Primed Circuit Board

SP_ME3 ....................
Parts rist
CA-ME3
SP-ME3 -----

COPYRIGHT © 1995 VICTOR COMPANY OF JAPAN, LTD.

No. 20526
Jul. 1995

Page 2

DC-ME3

- 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 manufacturers 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.).

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 1,500!) 10 W
resistor paralleled by a 0.15 11F AC-type capacitor between an exposed metal part and a
known good earth ground.

AC VOLTMETER

Jaw

Measure the AC volta e across the resistor .
with the AC voltmeter. 9 @ $113503 0
Move the resistor connection to each exposed a C ° m°rese"5iVY-)
metal part, particularly any exposed metal part
having a return path to the chassis, and 0,15; Ac TYPE
meausre the AC voltage across the resistor. -|}-
Now, reverse the plug in the AC outlet and a this
repeat each measurement. Any voltage vvv FELZfieefgosed
measured must not exceed 0.75VAC (r.m.s.). 15°09 10 metal part-
This corresponds to 0.5 mA AC (r.m.s.). Good earth ground

-Warnlng

.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.

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Page 31

2. Electrical Adjustments

CA-ME3

(Make the following adjustments after adjusting the head

azimuth.)
0st=0.775V
. Adjustment Standard
Item Adjustment Method Location Value Remarks
* Standard level 1. Connect an electronic voltmeter to the CNSOB. DeckA 1) The playback level varies when
1 (Playback Play back VTT-724 (1 kHz: -4st) to adjust the L: SFR303 the head is replaced so should
Level) semi-fixed resistors. R: SFR304 548", be adjusted.
Decks :1 dB Use an electronic voltmeter
L: SFR301 with an impedance of 100 k9
R: SFR302 °' mm-
* Recording 1. Connect a frequency counterto the TP5 and L311 85 kHz 1)Reacording tape Normal TS-B
2 Bias TP6(GND) , and perform a recording to adjust bias i 1kHz
Frequency frequency .
* Record / Play 1.. Connect an: electronic voltmeter to the CN308 to _
3 Bias Trap confirm the recorded values. L L301 -
; 2. Iflnsert the blank tape Deck A and Deck 8 for R : L302 _
: recording (Duubbing)
: 3. Play the ADeeck and adjust L301 and L302 so
that minimums output level.
* Bias Adjust 1. Connect an electronic voltmeter to the TP1 or TPZ SFR404 5mV 1)Reacording tape Normal TS-B
4 TP2,and perform a recording to adjust bias . TP1 SFR403
Record 1. Input a 1 kHz( -8.2st: 200mV) signal to AUX 'SFR30 Adjust with normal tape and
IPIayback terminals and record it on the left and right L" 5 200mV make sure that the left/right
Sensitivity channels . R : SFR306 level difference is 1.0dB or less
2. Connect an electronic voltmeter to the CN308 to in
confirm the recorded values.
3. If the values are not satisfied, adjust the semi»
fixed resistors and record the signal again to
confirm the recorded values.
* Erase ratio 1. Record a music source using the Metal tape.
6 check 2. Rewind and erase the recorded section. - _
3. Comfirm nothing can be heard.

I CD adjustment point

FE BIAS adjustment

1)

(Connected state the CN502)

2)
3)

4)

Connected a DC voltmater to the CN15.

Remove the Disc tray and REmove the adjust volume cover.

Remove the CD mechanism and remove the CD PCB cover of the bottom side.

Stop mode the CD and adjust VRO1 so that DC voltmeter OViZOmV

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