Jvc CAS 300 Service Manual

Page 1

CA~5300

JVC

PIC UP OPT-65
Isi MN662721RAM
Area Suffix
A . Australia
BS the U.K.
E ..... Continental Europe
4. G ..... Germany
13%;; GI Italy
gggg VX East Europe
5'34} US Singapore
32;: UT Taiwan
6 U ..... Other Area
@figfi
DIGITAL AUDIO
Contents
Safety Precautions ------------------------ 1'2 Maintenance of Laser Pickup ............. 1-45
Inportant for Laser P r OdUCtS -------------- 1'3 Replacemant of Laser Pickup ............. 1-45
Instruction 300k ------------------------- 1'4 Trouble shooting ......................... 1-46
Description of Major L313 ---------------- 1'15 Block Diagrams ......................... 1-51
Internal Connection of FL Display Tube .. 1-29
Disassembly Procedures .................. 1-30 Parts List ................................ 2-1
Adjustment Procedures ------------------- 1'38 Schematic Diagrams ................. Insertion
Flow of Functional Operation Printed Circuit Boards ............... Insertion
See diagnosis for pic up ................... 1-42
Until TOC is Read ...................... 1-44

No. 20496
Jan. 1995

Page 2

CA-SSO O

- 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.).

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 1,5009 10 W

resistor paralleled by a 0.15 11F AC-type capacitor between an exposed metal part and a
known good earth ground.

Measure the AC voltage across the resistor E afaxggngggm
Wlth the AC voltmeter. ohms/volts, _ ' .
Move the resistor connection to each exposed a o- 0' "Gre sens't'V'tY-l
metal part, particularly any exposed metal part
having a return path to the chassis, and 0.1511F Ac TYPE
meausre the AC voltage across the resistor. -||-
Now, reverse the plug in the AC outlet and H: 5
repeat each measurement. Any voltage vv 23,122,305
measured must not exceed 0.75VAC (r.m.s.). 150°910W metal part-
This corresponds to 0.5 mA AC (r.m.s.). Good earth ground

-Warnmg

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.
. It is essential that safety critical components are replaced by approved parts.
5. If mains voltage selector is provided, check setting for local voltage.

<5

1-2 (No. 20496)

Page 39

I Deck section

I Deck adjiustment point

CA~S3OO

L '0 R205 O
REC LEVEL I
R R206 H O
r . H _
r ENJ-083A DOLBY T.P
L R355 I331 H I;
BIAS ADJ H L
R 23 R356 rPsoi
L R333
8 PB LEVEL
R R334 . H E L
H
BIAS TP H 'E- L 0 m; A PB LEVEL
TP201 H R 3312 E R
TP301 V V
R [1324 R303 L
B FREQ A FREQ
I R304 R Figure3
SPEED CONTROL
--J '71 L-' '
n94 *HEATSINK
ENH-251-1
FRONT REAR
ENH-251-3
Figure4

1. Measuring instruments
Audio frequency signal generator ( Odbs output at the 600 ohm output terminal from 50Hz to ZOKHz)

Electronic voltmeter
Frequency counter
Wow & Flutter meter

Distortion Meter with band pass filter

Attenuator (600011111 impedance)
A resistor with 6009

Standard Tape

0st=0.775V

Tape No. Frequency Level (Wow & Flutter) Purpose
VTr-703L 10kHz -10st Head azimuth , Frequency Response
VTT~712 3000Hz ()st 0.025%WRMS Tape Speed . Wow& Flutter
VTT~724 1kHz -4st Standard Level
TMT-6447 - - Blunk Skip
TMT-6247 , TMT-6237 - - Music Scan
TS-8 -- - Recording standard Normal : UR
TS-11 - - Recording standard METAL :MA
TS-10 - - Recording standard Cr02:5A
GTG-N (Cf-100M) - - FonNard / reverse play torque measuring
TW-2231 - - Feed fonNard/rewind torque measuring
C-120 Tape - - Comfirming the tape running

(No. 20496) 1-39