Jvc TDEX 90 Service Manual

Page 1

TD-EX90

JVB
SERVICE MANUAL

TD-EX90

Area Suffix
C ------------ Canada
-- USA.
mm mm cmmm -- Other Areas
-- Hong Kong
- China
" Singapore
-- Taiwan
B ------------ U.K
E """"" Continental
Europe
EN ----- Northan Europe
EE ------- Eastern Europe
Contents
Safety Precautions ------------------------ 1-2 Block Diagrams ----------------------------- 2-15
Important for Laser Products - - 1-3 Schematic Diagrams ------- -- 2-16
Instructions ----------------- - 1-4~20 Location of RC. Board Part ----- -- 2-18
Location of Main Parts -------------------- 2-1 Analytic Drawing and Parts List - 3-1
Removal of Main Parts ------------------- 2-2 Electrical Parts List ------------- -- 3-7
Main Adjustment -- Packing -------------------------------------- 3-12
Out Line Of Main IC ----------------------- 2-12
No.20712

COPYRIGHT © 1995 moron COMPANV OF JAPAN. LTD.
July 1 998

Page 2

TD-EXQO

1-2

-Safety Precautions

1.This 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 funher relieve the manufacture of responsibility for personal injury or property damage resulting
therefrom.

3. Many electrical and mechanical pans 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
replacement 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 pans, 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 continued 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, 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 pans of the cabinet,particular1y 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 1,500910W resistor paralleled byaD.15uF
AC-type capacitor between an exposed metal part and a known good earth ground,

Measure the AC voltage across the resistor with the AC voltmeter. Ac VOLTMETER
Move the resistor connection to eachexposed metal a (Havingtooo
part, particularly any exposed metal part having a ohms/volts,
return path to the chassis, and meausre the AC 0' more 59'5me
voltage across the resistor. Now, reverse the plug in
the AC outlet and repeat each measurement. voltage o_15uF Ac TYPE
measured Any must not exceed 0.75 V AC (r,m,s.). II .
This corresponds to 0.5 mA AC (r.m.s.). " 33:21,?
' Wv each exposed
15009 10W metalpart.

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. It mains voltage selector is provided, check setting for local voltage,

A CAUTION Burrs formed during molding may be left over on some parts of the chassis. Therefore,
pay attention to such burrs in the case of preformlng repair of this system.

Page 24

TD-EX90

Main Adjustment

1. Measuring instruments required for adjustment
(1) Low frequency oscillator

This oscillator should be capable of outputting OdB

(0.775V) at the snow terminal at an oscillation tre~

quency of 50 - ZOkHz.

Attenuator (Impedance: 600 Q )

Electronic voltmeter

Standard tapes tor mournment

VT712 (for measuring the tape speed and wow flatter)

VT724 (Reference level) (1 kHz)

TMT735 (for measuring-the playing (playback)

frequency characteristics) (1 kHz and 12.5kHz)

TMT6447 and TMT6448 (for music scanning)

VT705 (12.5kH2) (for adjusting the head azimuth)

Standard recording tape

AC-225 (TDK AD), AC-514 (TDK SA), AC-713 (TDK

MA) or equivalent

(Be sure to use only the standard recording

(measurement) tapes specified by this division).

(2)
(3)
(4)

(5)

I Arrangement of adjusting positions

(6)
(7)
(8)

600 Q resistors and so forth (for attenuator matching)
Distortion meter (band pass filter)

Torque gauge (cassette)

For adjusting the torque related to CTG-N,TW211,
Tw2121, TW2231 and TW2241

Wow flatter meter

Frequency counter

M300 gauge (Gauge M300)

Band pass filter

(9)
(10)
(11)
(12)

2. Setting of the respective switches and volume
knobs
- Dolby NR switch : OFF
- Reverse mode : ON
- Power supply switch : ON

Main RC. boaidaesombty

BMW ecu board essembty

TP
CNMM
L e n DobyNRtestpoim

.VRBSI

[I

VRA

Dolby RC. hoax! aseembiy

Adjustment at recordan level

Fig. 1

Adjustment oi recording!

playing Adjustment ol

' 31 .

ntugtnrcgeordlng W'nu trequancy
bits current)

VRSOl mm
I

[REQMPLAV]
RC. mint memory

VRSOZ I
R
L _ R
Adjustment at
playing level VRZOG VR219

I

Adjustment 0' bias
oscillation lreqmmcy

Fail

:1

are

W W

TP32(HOT)

°®

Fig. 2

Bias metering terminal