Jvc XLE 51 BK Service Manual

Page 1

.JVB
SERVICE MANUAL

MODEL No. XL-E51BK

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'COMPACT
DIGITAL AUDIO
Contents
Sa'er Precautions ........ r r r r . . Page 1- 2 Flow of Operation Untrl TOE 15 Read ....................... Page 1~22
Important for Laser Products .................................. Page 1' 3 Pickup Maintenance Procedures V r . V . . Page 1-23
Instruction Back .................. Page 1- 4 Applrcahon Pomts for Grease . Page 1724
Descripnon of Major LSI. V Page 1-10 Troubleshooting .................. , Page 1»25
Internal Block Diagram of mm lC H. ................. Page 1-16 Block Diagramv--m-r-~---~ - - - - - - , , , . Insertion
Internal Connections for the FL Display Tube ............ Page 1-17 Schematic Diagrams --------- - , ("597mm
Disassembly Procedures ............... Page 1718 Prrnted CVCUiI Board ASSY 159mm
Pickup Replacement Procedures Page 1-20 Connecfiun Dlagram r, . . . . V lnsenion
Adjusn-mant Procedures ,,,,,,,,,,,,,,,,, 0 Page 1721 Parts List ................................... Separakewolume 1nserlion
No. 20100

Mar, 1989

Page 2

I XL-E51BK

1 .

P

rSafety Precautions

The design of this product contains special hardware and many circuits and components specially for safety pur-
poses. 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. Service should be per-
formed by qualified personnel only.

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 manufacturer of responsibility for personal injury or property damage resulting therefrom.

. Many electrical and mechanical parts in the product 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 Manuel. 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 sub-
stitute replacement which does not have the same safety characteristics as the recommended replacement part shown
in the Parts List of Service Manual may create shock, fire, or other hazards.

. 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 rte-assembling.

. Leakage current check (Electrical shock hazard testingl

After reassembling the product, always perform an isolation check on the exposed metal parts of the product
(antenna terminals, knobs, metal cabinet, screw heads, headphone lack. control shafts, etc.) to be sure the product
is safe to operate without danger of electrical shock.

00 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 part 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 0.5 mA AC lr.m.s.l.

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 sensi-
tivity in the following manner. Connect a 1,500 $1 10 W resistor paralleled by a 0.15 uF AC~type capacitor be-
tween an exposed metal part and a known good earth ground.

Measure the AC voltage across the resistor with the @ AC YOLTMETER
AC voltmeter, (H'v'ng 100? ohms/volt,

_ or more sensitivity l
Move the resistor connection to each exposed metal
part, particularly any exposed metal part having a u-
return path to the chassis, and measure the AC volt- 5" c 7""
age across the resistor. Now, reverse the plug in the Place this probe
AC outlet and repeat each measurement. Any voltage m on each exposed
measured must not exceed 0.75 VAC (r.m.s.). This isooa lOW metal part.
corresponds to 0.5 mA AC (r.m.s.).

Good earth ground

014de

-Warning

. 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.

1-2 (No. 20100)

Page 45

Focus Servo Secfion

N0

XL E51BK

loaded when the
R572 shon has been
removed?

VES

Check |C4OL K2851,
0554. 0555.

Are me voltages
K2851 N9 Checkrhe powersup-
G): 712v, ply circuii.
@= + 12V?
YES
Does (he pickup lens
move up and down No Arerhevoltages +9V N0
when me "av is anhe 0554 collector
Closed using the and-SVattheOESS
OPEN/cmss swimm °°"°-
YES
YES
Does me following Dnesa «0,5v wave- Does me followmg
waveform appear at form appear for ap- WBVB'O'm appear 3
TPa (FE; immediately proximately 3 seconds |c401 ® lor approx:-
aher a disc is loaded at approximately 2- WWW 3 seconds af
when R572 is NO Check the pickup and second imervals at me no ter closing?
shorted7 conneckions imm 0554 aminer after
|C501 and (he pickup. closing? I I l I {3.
_% Aunwx. 0ND
UV :zv
lows ,
f-zs-l 15 us
VES YES
VES
Dosslhe signal wave- Does the following
form shown in Figure waveform appear at
below appear at NO _ the 0553 eminer for
the |C502®|mrnedi- Defecwe K3502 Check me wckUD and apprDXImakely 8 se-
aiely after a disk IS ermg- conds?

Guam.
l--l

25

Defective K3401, or
see the Feed Servo
Secrion and Lnading
Circuii Secrion.

N0

YES

Deiecrlve
0554, 0555.

lC851,

® The waveform a1 the start of focus zero
cross play.
Focus zero cross signal just before play start:
pulse width is about Ims.

lmSec

+5V

---ov

Defective 0552,
0553 and periphery.

(No. 20100) 1-27