Jvc UXZ 7 MDR Service Manual

Page 1

UX-Z7MDR

JVC
SERVICE MANUAL

MICRO COMPONENT MD SYSTEM

UX-Z7MDR

Area Suffix

E -------- Continental Europe

@R-D-s
M D LP

uuuuu

COMPACT
DIGITAL Aunlo
TABLE OF CONTENTS
1 Important Safety Precautions ........................................................... 1-2
2 Disassembly Method ......................................................... 1-5
3 Adjustment method ......................................................... 1-37
4 Description of major le ............................................................... 1-44
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD. No_22042

2003/02

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UX-Z7MDR

SECTION 1
Important Safety Precautions

1.1 Safety Precautions

(1) This design of this product contains special hardware and exposed metal part and a known good earth ground
many circuits and components specially for safety purposes. Measure the AC voltage across the resistor with the AC
For continued protection, no changes should be made to the voltmeter.
original design unless authorized in writing by the man- Move the resistor connection to each exposed metal part,
ufacturer. Replacement parts must be identical to those particularly any exposed metal part having a return path to
used in the original circuits. Services should be per- the chassis, and measure theAC voltage acrossthe resistor.
formed by qualified personnel only. Now, reverse the plug in the AC outlet and repeat each

measurement. Voltage measured any must not exceed 0.75

(2) Alterations of the design or circuitry of the product should ,
VAC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.).

not be made. Any design alterations of the product should

not be made. Any design alterations or additions will void AC VOLTMETER
the manufacturers warranty and will further relieve the a (Having 1000
. .. . . ohms/volts,

manufacture of responSIbility for personal injury or property or more sensitivity)
damage resulting therefrom. =

(3) Many electrical and mechanical parts in the products have 0315/1 F AC TYPE
special safety-related characteristics. These characteris- -II-| Place this
tics are often not evident from visual inspection nor can the 'WV . , : 23:12: sed
protection afforded by them necessarily 'be obtained by us- 15009 10W metal pg:
ing replacement components rated for higher voltage, watt-
age, etc. Replacement parts which have these special safety Good earth ground
characteristics are identified in the Parts List of Service Manu- 1.2 Warning
al. Electrical components having such features are iden-

(1) This equipment has been designed and manufactured to
tified by shading on the schematics and by (A) on the meet international safety standards.

Parts List in the Service Manual. The use of a substitute re-
placement which does not have the same safety character-
istics as the recommended replacement parts shown in the

Parts List of Service Manual may create shock, fire, or oth- (3) Repairs must be made in accordance With the relevant
er hazards. safety standards.

(2) It is the legal responsibility of the repairer to ensure that
these safety standards are maintained.

(4) It is essential that safety critical components are replaced

(4) The leads in the products are routed and dressed with ties.
by approved parts.

clamps, tubings, barriers and the like to be separated from
live parts, high temperature parts, moving parts and/or (5) If mains voltage selectoris provided, check setting for local
sharp edges for the prevention of electric shock and fire voltage.

hazard. When service is required. the original lead routing 1.3 Caution

and dress should be observed, and it should be confirmed Burrs formed during molding may be left over on some parts
that they have been returned to normal, after reassembling. of the chassis.

(5) Leakage shock hazard testing) Therefore, pay attention to such burrs in the case of pre-

After reassembling the product, always perform an isolation forming repair Of this system.

check on the exposed metal parts of the product (antenna 1-4 Critical parts for safety

terminals, knobs, metal cabinet, SCFBW heads, headphone In regard with component parts appearing on the silk-screen
jack, COhVOI shafts. etc.) to be sure the PTOdUCt is safe to printed side (parts side) of the PWB diagrams, the parts that are
operate without danger Of electrical ShOCk. printed over with black such as the resistor ( - ), diode ( h )
Do not use a line isolation transformer during this check. and ICP (. ) or identified by the " A " mark nearby are critical

- Plug the AC line cord directly into the AC outlet. Using a for safety.

"Leakage Current Tester", measure the leakage current When replacing them, be sure to use the parts of the same type
from each exposed metal parts of the cabinet. particular- and rating as specified by the manufacturer. (Except the JC version)
ly any exposed metal part having a return path to the
chassis. to a known good earth ground. Any leakage cur-

rent must not exceed 0.5mA AC (r.m.s.).

- 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 ohm 10W resistor
paralleled by a 0.15 pF AC-type capacitor between an

1-2 (No.22042)

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UX-Z7MDR

2.1.2 Removing the CD mechanism assembly Amp board CD h . .
(See Fig.4 to 7.) CN302 mec anlsm assy
- Prior to this procedure, remove the metal cover. ,
(1) Remove the card wire from the connector CN302 on amp
board on the left side of the main body.
(2) Remove the three screws C on top of the body that attach
the CD mechanism assembly.
(3) Lift the CD mechanism assembly upward and move it
backward to remove.
(4) Remove the card wire from CN606 on CD sen/o board, on
the bottom of the CD mechanism assembly.

Amp board
CN302

CD mechanism ass'y

CD mechanism ass'y
\ 00

CD mechanism ass'y CD servo board
CN606

1-6 (No.22042)

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UX-Z7MDR

2.4.9 Reattaching the loading assembly
(1) Reattach the eject bar to the UD base. (Fig.15 and 21)
(2) Reattach the slide bar to the loading mechanism chassis while fitting the boss marked k to the eject bar slot. (Fig.21)
(3) Slide the slide bar and the eject bar in the direction of the arrow in Fig.20 and reattach the cartridge holder assembly using the
two screws I. (Fig.21 and 22)

ATTENTION:
Make sure the pin of the eject lever marked | is fitted to the slot of the eject bar marked rn at the bottom of the loading mech-
anism chassis after moving the eject lever and the loading slider of the cartridge holder assembly in the direction of the arrow.
(Refer to Fig.22)

@-H

Cam switch board
, a Point marked

,»l:|

Slide bar

. __l

Fig.21

Cartridge holder assembly
Ditch m

Loading slider

Eject lever

(No.22042)1-31

Page 58

UX-Z7MDR

4.17 LA1838 (lc1): FM AM IF AMP&detector, FM MPX Decoder
- Block Diagram

30 29 28 27 26 25 24 23

REG

AM FM
DECODER
MIX REAMF ANITVBIRDIE

TEREO
5N
SW

so vco FF FF /3 F; FILOT
COMP 384KH2 38k 19k2 19k/LS DET

AM/FM

lFrBUFF
TUNING STEREO
DRIVE DRIVE

- Pin Function

Pin No. Symbol I/O Function
1 FM IN I This is an input terminal of FM IF signal.
2 AM MIX 0 This is an out put terminal for AM mixer.
3 FM IF I Bypass of FM IF
4 AM IF I Input of AM IF Signal.
5 GND - This is the device ground terminal.
6 m 0 When the set is tunning,this terminal becomes "L.
7 m 0 Stereo indicator output. Stereo "L", Mono: "H"
8 VCC - This is the power supply terminal.
9 FM DET - FM detect transformer.
10 AM SD - This is a terminal of AM ceramic filter.
11 FM VSM 0 Adjust FM SD sensitivity.
12 AM VSM 0 Adjust AM SD sensitivity.

13 MUTE l/O When the signal of IF REQ of 1C121(LC72131 ) appear, the signal of FM/AM IF output. //Muting
control input.

14 FM/m | Change over the FM/AM input. "H" :FM, "L : AM
15 MIST 0 Stereo : H", Mono: "L"

16 L OUT 0 Left channel signal output.

17 R OUT 0 Right channel signal output.

18 L IN I Input terminal of the Left channel post AMP.

19 R IN | Input terminal of the Right channel post AMP.

20 R0 0 Mpx Right channel signal output.

21 LO 0 Mpx Left channel signal output.

22 MPX IN I Mpx input terminal

23 FM OUT O FM detection output.

24 AM DET 0 AM detection output.

25 AM AGC I This is an AGC voltage input terminal for AM

26 AFC - This is an output terminal of voltage for FM-AFC.
27 AM RF I AM RF signal input.

28 REG 0 Register value between pin 26 and pin28 besides the frequency width of the input signal.
29 AM OSC - This is a terminal of AM Local oscillation circuit.
30 OSC BUFFER 0 AM Local oscillation Signal output.

1-58 (No.22042)