Jvc XLV 251 TN Service Manual

Page 2

XL-V251TN /XL-V2523K

XL-V1 51 TN I XL-V1 523K

- 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 authorised in writing by the manufacturer. Replacement parts must
be identical to those used in the original circuits.

. Any unauthorised design alterations'or additions will void the manufacturer's guarantee;

furthermore the manufacturer cannot accept responsibility for personal injury or property
damage resulting therefrom.

.'Essential safety critical components are identified by (A) on the Parts List and by shading

on the schematics ,and must never be replaced by parts other than those listed in the
manual. Please note however that many electrical and mechanical parts in the product have
special safety related characteristics. These characteristics are often not evident from visual
inspection. Parts other than specified by the manufacturer may not have the same safety
characteristics as the recommended replacement parts shown in the Parts List of the service
manual and 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 re-assembling.

Warning

. Service should be performed by qualified personnel only.
.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.
. lf mains voltage selector is provided, check setting for local voltage.

1-2 (No. 20301 U)

c.

Page 30

XL-V1 51 TN lXL-V1 523K
XL-V251 TN lXL-VZSZBK

Troubleshooting

Power on

l

Does the Fl.
indication
light
normally?

YES

Can the disc
tray be moved
in and out using
the OPEN]
CLOSE button?

NO ['r'o'IEa'din-g- - ' ' .

YES

Does the
indications on
the FL display
show----when
the disc tray is
closed?

The following shows the status of the various circuits from
turning on the power to the start of disc play .

1

section. I
|. __________ J

YES
Can it read No Does the disc N0
TOC? rotate?
YES ¢YES
Ca t i th lsthle tdrgcking loop
n l p a e app Ie
r To spindle 1 NO fir. "ackgt TF7(TE)
l__EE*PL-_____l 5 YES
- V
l
ls the RF
Check the waveform Can a 1V/dlv,I
me up NO normal? sec/div
YES waveformbe
observed?
r ----------- -.
: To tracking :
I section, I NO Can it search to
----.....--- each track
L To feed section. JI correctly? I'
----------- I
YES
. Can an
TpaudIO No Does it sound instantaneous YES
CIchIt. OK? 1 Vp waveform

._-__-----.--. NO
IL To front sectIon._II<-

1-30 (No.20301l

YES

Check general
operations

Are all operation
keys on the
front panel and
the FL display
correct?

YES

OK

be 0 served at

RF TP37
i No
Check the
pickup.
'iE?piEcfi€"".+_
I
1 sectIonI J

Does the pickup NO
lens move up No
and down with Isthere 0V at
the tray closed? 9'09 0f P5017
YES
YES
.To' ?ocus'""r
Does the laser I section 1
light for ----------- -
approximately 8
seconds afterthe Is there + 5V at
tray IS NO W I f
closed?(Check the $3353le N0
laser by power seconds after the
meter) tray is closed 7
YES YES
Is focus applied Check the
for N0 pickup and the
approximately 8 connections
seconds after from P501 to
the tray is the pickup.
closed? (Check
the lens
movement
visually?) Check the con-
nections
between lCZOl
YES and P501,
"T'o'sEinEIE' "1
section. J