Jvc AL E77BK Service Manual

Page 1

Contents

Safety Precautions ..
lnstruciion Book

Technical Explanations .............
I Programmed Tune Selection .
I IC901 (MB 88401M-304K) Pin Funcuons
Block Diagram ..........
Removal Procedures ..
I Removal of the Dust Cover .
I Removal of the Front Escutcheon
Adjustment Procedures .......
I Offset (Tracking Error! Adjustmen!
I Tonaarm Lead-in Adjustment ..........

H-Iddddd-I-ld
NOOUGCUI-§WQ

Page

I Adjustment of Tune Selection Sensitivity
(DC Sensitivity) ............................................. 17

I Adjustment of Tune Selection Sensitiviry

(AC Sensitivity) ............................................. lv7
I Motor Speed Adjustment . l-7
Cartridge Replacement . , 1-7
Troubleshooting .. _ 1-8
Carrier Cord Suspensron ., 111
I Suspending Procedure ., 111
I Fixing of Tonearm Section . . 1/11
Schematic Diagram lnsa't ion

Parts List .............. .. Separate-Volume Insertion

This manual combines two single volumes; Service manual and Parts list,

No.2896 .
Feb. 1986;

Page 2

AL-E77BK

Safety Precautions

1. The design of this product contains special hardware,

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 pans must be identical
to those used in the original circuits. Service should be
performed by qualified personnel only.

2. Alterations of the design or circuitry 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.

3. Many electrical and mechanical parts in the product
have special safewArelated characteristics. These charac-
teristics 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 Service
manual. The use of a substitute replacement which does
not have the same safety characteristics as the recom-
mended replacement part shown in the parts list in
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/or the like to be
separated from live parts, high temperature parts, mov~
ing parts and/or sharp edges for the prevention of elec-
tric shock and fire hazard,

When service is required, the original lead routing and
dress should be observed, and they should be confirm-
ed to be returned to normal, after re-assembling.

5. Leakage current check

(Safety for electrical shock hazard)

After re-assembling the product, always perform an

isolation check on the exposed metal parts of the

Products (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 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 mV
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. Con-
nect a 1500 S] 10 W resistor paralleled by a 0.15 uF
ACetype capacitor between an exposed metal part
and a known good earth ground. Measure the AC
voltage across the resistor with the AC voltmeter.
Move the resistor connection to each exposed metal
part, particularly any exposed metal part having a
return path to the chassis, and measure the AC
voltage across the resistor. Now, reverse the plug in
the AC outlet and repeat each measurement. Any
voltage measured must not exceed 0.75 V AC (r.m.s.).
This corresponds to 0.5 mA AC lr.m.s.).

@ AC VOLTMETER
(Having 1000 ohms/volt,
or more sensitivity.)

0.15 F AC TYPE

Place this pm be
on each expnsed
metal part.

1500 low

Good earth ground

CHECKING YOUR LINE VOLTAGE
(Except for U.K., Continental Europe and Australia)

Before inserting the power plug, please check this setting to see that it corresponds with
the line voltage in your area. If it doesnt, be sure to adjust the voltage selector switch to
the proper setting before operating this equipment. The voltage selector switch is located

underneath the platter.

CAUTION: Before selecting the "Voltage selector switch to proper voltage, disconnect

the power plug.

LIME

VCLTS

1-2 (No. 2896)

Page 15

Pour Ia lecture automathue

Pour iire les moroeaux dans i'ordre depuis le

premier aulomattquemenl. opeter de la maniere

suivante,

4-1 Placer le bouton SPEED seion ie disque.
Disque 83 tours 1/3: 33"

Disque 45 tours: "45

4-2. Placer le bouton SENSOR sur la meilleura
position
Se referer a Réglage de la position du bouton
SENSOR".

4.3 Presser ia touche START/STOP; la lecture
automathue commence Ouand elle est lime
le bras de iecture retourne sur son support at
ie plateau s'arréte.

Remarque:

. Celle platlne tcume-dhque est concue pour
pvoduire un sllencleux de quelques swondes
upres que le bras do lecture coll descendu sur
h surlace du disque; 08d est pour la
oommodlfi en lecture progvammée.

Réglage de ll pooitlon du boutan SENSOR
S'assurer que le bouton SENSOR suit a ia position
optima pour la iecture programmée et indexée, Sil
ne l'est pas le bras de lecture risque d'etre abaisse
avant ou apres le debut du morceau programme ou
soulevé au milieu dun morceau (pas en lecture
indexée). Pour selectionner la posmon optima avant
la recherche, appuyer sur la touche RANDOM
ACCESS PROGRAM out possede (e meme chiffre
que ie dernier moroeau du disque puis presser Ia
touche START/ STOP. Régler alors le bouton
SENSOR pour que le dernier morceau suit joue
apres la recherche. Par example guano un disque
a ping morceaux. appuyer sur la touche RANDOM
ACCESS PROGRAM "5" et presser la touche
START/STOPV Régler la position du boulon
SENSOR sur LOW( NORMAL ou HIGH de maniere
a ce que ie cinquieme morceau sort joué apres ia
recherche.

Pour la lecture programmée

Pour lire tes morceaux dans n'impone quel ordre

voutu. opérer de la maniere suwante.

571 Régler le bouton SPEED selon le disque
Bisque 33 lours 1/3' "33"

Disque 45 tours: 45"

5-2 Régler le bouion SENSOR sur la posilion
optima.

5~3 Programmer les moreeaux avec les touches
RANDOM ACCESS PROGRAM La pror
grammation peul cons1ituerde 15 moroeaux
maximum parmi les 8 moroeaux dune lace du
disque, dans n'importe quel ordre,
Hmamuec
0 Un disque pouédant neul morceaux au

plus doll élre Iu manuellement apréa que
hull morceaux on! élé lua.

5-4. Si les touches RANDOM ACCESS
PROGRAM ne sont pas pressées correcte-
ment, appuyer sur la touche CLEAR et repro-
grammer depurs Ie debut,

Remuo:

is! In louche START/STOP esl preetée
pendant la lecture programmée, oellecl
at uni annulée.

Voor automatlsche weergave

Veer de volgende handelingen uit voor auto»

matische weergave in volgorde vanal de eerste

passage,

4A1 Stei de taerentaI-keuzeschakelaar (SPEED)
overeenkomstig het toerental van de plaat in,
33-1/3 Ipm pleat "

45 rpm pleat:

4A2 Zet de SENSOR-keuzeschakeiaar in de

meest geschikte stand, Zie instellen van de
SENSOR-keuzeschakelaar"

4-3. Druk de START/STOP-ioets In: automatische
weergave wordt gestart. De loonarm keerl
terug naar de toonarmsteun en hel draai-
plateau stopt met draaien wanneer weergave
beeindigd wordt.

Opmeflrlng:

0 Den draallalel I: :9 onlworpen, dnt da eersla
pur sekonden, nadat de toonann op hot
opporvlak van de grammoloonplaat landt, nlet
warden weergegwen; dit ls voor het be-
dloningsgemak tlidens geprogrammeerde
weergave.

Imtellon van de SENSOR-keuzeschakelaar

Kontroleer dal de SENSOR~keuzeschakelaar in de
optimale stand staat voor geprogrammeerae
weergave of index-weergave. Mocht dlt niet het
geval zijn dan kan hel voorkomen oat de toonarm
voor oi na het begin van de geprogrammeerde
passage daali of in het midden van de passage
plotseling stijgt (met bii indexweergave). Om de
uplrmale stand te kiezen voar opsporing, de
programmeringstoets (RANDOM ACCESS
PROGRAM) mel hetzelfde nummer ats de Iaatste
passage op de plaat indrukken en daarna de
START/STOP-toets indrukken Nu de SENSOR,
keuzeschakelaar zodanig instellen dat de laatste
passage na opsponng weergegeven wordt
Wanneer een plaat bijvoorbeeld vui passages
bevat, taets de programmeringstoets "5" RANDOM
ACCESS PROGRAM en de START/STOPAtoets
indlukken. Eveniueei de SENSOR-keuzeschake-
laal on Low. NORMAL of HiGH Instellen zodat de
wlde passage na opsponng weergegeven wordl.

Voor geprogramrneerde weergave

Voer de volgende handeiingen uit om passages in

elke willekeurige volgorde weer te geven.

54, Stel de toerentai-keuzeschaketaar (SPEED)
overeenkamstig het toerental van de plaat in,
33-1/3 tpm plaat: ""33

45 ipm piaai: 45"

52 Zet de SENSOR-keuzeschakelaar in de
meesl geschtkte sland.

5-3. Programmeer de passages mobiv. de pro-
grammeringstoelsen (RANDOM ACCESS
PROGRAM). Hel programme kan maximal 15
Willekeunge weergaven van 8 passages aan
een kant van een grammoioonpiaat bevatten.

Oprnerklng:

OEen grammoloonplaat, die 9 of meet
passages hem, dlem no alspelen van
acht passages verder handbedlend le
warden mergegeven.

5-4. Wanneer de programmeringstoetsen
(RANDOM ACCESS PROGRAM) niet juist
ingedrukt zijn, de wistoets (CLEAR) indrukken
en overnieuw begmneni
Opmerldng:

UWanneer de START/STOP-mets wordt
lngedrukl lljdens geprogrammeerde
weerglve, woidt het programma uh bet
geheugen gewllt.

_12_

A 77BK

Reproducclén autométlca

Opere de la sigulenle manera para reprodumr

automaticameme Ias melodies comenzando per |a

primera:

44, Ponga la perilia SPEED en la velocidad
correcta.

33" para discos de 33-1/3 rpm
45" para discos de 45 rpm

4-2 Ponga la perilla SENSOR en la mejor posicion
Reliérase a COmo aiuslar la posicion de la
perilla SENSOR".

4-3 Presione ei botén START/ STOP para miciar Ia
reproducciorr automatica, Cuando termina Ia
reproduocién el brazo retoma a su posimon
original y el locadiscos se devene.

Nola:

O Para eu conveniencia duranle la reproducclén
program ate tooadiscu ma diseflado
para slienclam par varies segmdoo dupués
qua ol brazo be]: sobre la supefllcls del disco.

Como aiustar Ia posicién do In puma
SENSOR

Asegdrese que (a perilla SENSOR esté en is pos-
cibn Optima para la reproducciOn progmmada 0 la
reproductién indicadora En case contrario el
brazo puede bajarse antes 0 después de la melodia
programada o elevarse durante su reproduccién,
excepto durante la reproduccién irdicadora, Para
seleccionar ta posicibn Optima antes de la
basqueda. presione eI baton RANDOM ACCESS
PROGRAM con el ndmero de ia ultima melodla del
disco y luego presione el botén START/STOP.
Ahom ponga la perilla SENSOR de inanera tal que
se reproduzca ta L'tltlma melodia deldisco despues
de la basqueda Par ejemplo. presrone en botOn
RANDOM ACCESS PROGRAM 5" y el boum
START/STOP cuando el disco tiene cmco
melodias. Ponga Ia perilla SENSOR en la pasicxén
LOW. NORMAL 0 HIGH de manera tal que se
reproduzca la quinta melodia upspués de la
basqueda,

Reproduction progmmada

Para locar ias melodias en cualquler orden

deseado. opere de la siguiente marera:

S-t. Ponga la perilla SPEED en la velocrdad

ecza.

para discos de 33-1/3 rpm

"45" para discos de 45 rpm

5-2 Ponga la perilla SENSOR at la posicion
optima

5-3 Programe las melodias con los batches
RANDOM ACCESS PROGRAM. La pro-
gramacién admits urr ma'ximote l 5 meiodias
(8 melodias de un Iado del diam) en Cualquier
orden.

Nola:

0 Un dlco qua Ilene nueve amés molodias
tiene que oer raproducldomanulltmnte
después de reproduei Ins echo
primem.

5-4V Si comete un error en ia oolacicn tie los

bmones RANDOM ACCESS PROGRAM

presione el botOn CLEAR y einicie ia pro-

gramacton.

Noll:

- Tamblén Ie nnula em lumaru si dumnle
la reproducclibn programsu sC pmslona
cl batén START/STOP.

(No. 2896)