Akai GXR 99 Service Manual

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Akai GXR 99 Service Manual

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Page 2



Abbreviation Explanation Abbreviation Explanation
AC Alternating Current MEMO MEMOry
A/D Analog/Digital MICOM MIcroCOMputer
AF Auto Fader MIN MINute
AM Auto Monitor MML Maximum Modulation Level
AMP AMP liïŹer MOL Maximum Output Level
AR Anti Recording MPX Multi PleX
AT BIAS Auto Tuning BIAS NC Not Connected (No Connection)
ATT ATTenuator NFB Negative Feed Back
BEF Band Elimination Filter NR Noise Reduction
BSS Blank Search System OSC OSCiJlator (OSCillation)
CH CHannel P Pulse
CN Cam Norma] P.B. Play Back
COMP COMParator QMSS Quick Memory Search System
CR Cam Reverse R Right
CRI..P Computer Recording Level Processing REC RECord (RECording)
CS Cam Stop REV REVerse
D Down ROT ROTation
D/A Digital/Analog REW REWind
DC Direct Current SEC SECond
EQ EQualizer SEPP Single Ended Push Pull
FF Fast Forward SIG SIGnal
F LD F Luorescent Display SPECT SPECT mm
FWD F orWarD SW SWitch
H High TP Test Point
HPF High Pass Filter U Up
IND INDicator VCA Voltage Control Attenuator
IPLS Instant Program Location System VOL VOLume
LED Light Emitting Diode VR Variable Resistor
M Motor X-™TAL crysTAL

Page 36

. . .and then some
. . .et autres

Quick reverse

Stereo cassette decks employ a A-Irack record»
ing/playback system, The lirst hall of the ste-
reophonic recording or playback takes place on
tracks 1 and 2 (side A), and the second halt
takes place on tracks 3 and 4 (side B). In a con-
ventional cassette deck. you must turn over the
cassette tape if you want to record or play back
on a different side The Akai GX-RQS is equipped

Inversion rapide

Les magnétocassettes stéréo incorporent un sys-
teme d-˜enregistremcut/reproduction a 4 pistes.
La premiere moitiĂ© de l-˜enregistrement on de la
reproduction stĂ©rĂ©ophonique s-˜etTectue sur les
pistes 1 et 2 (face A), et la seconde moitiĂ© s-˜etfec-
tue sur les pisles 3 et 4 (face B). Avecun magneto-
cassette conventionnel, vnus devez retourner la
bande cassetm Si vous voulez enregistrer on re»

wrth the quick reverse system The tape travel di»
rection changes automatically at the end of the
tape. Therelore. there is no need to turn over the
cassette tape yourself.


You can also manually change the tape travel di-
rection by depressing the forward or reverse
button without first pressing stop. The direction
indifators will show the tape travel direction (<(
0T )) .


-˜ For quick reverse operation. always use a tape With very clear

leader tape sections.

0 When a prerecorded tape is used for one-cycle (forward to
reverse) recording, the tirst one second of the reverse side of the

tape will not be erased
Please manually erase this section.

0 During quick reverse operation. no recording will be made for 0.6


0 The IEII SEIEII'IIII has no effect during intro scan and blank search

operation 5

The microprocessor -œbrain" and infrared "eye" of the Akai GX-RQQ allow for

maximum convenience in your recording and playback operations


1. Press the Reverse selector (IIEI SELECT) to set the mode,

: Indicates the tape can travel in only one direction depend-

ing on which button is depressed either (4 i or (>)

B -˜ Indicates one full cycle. The tape will play to the end oi side
t,reverse, play side 2 and then stop

C: Indicates infinite play back. The tape wrll continue to
reverse and playback both sides until you change the lunc-




produire sur I'autre face. Le GX-R99 Altai est
Ă©quipĂ© d-™un systĂ©me d-˜inversion rapide. Le sens
de de-™tiiement de la bande change automatique-
merit a la {in de la bande. Vous n-™avez done pas
besoin de retourner vous-méme la bnnde cassette.

Vous pouvez Ă©galemcnt changer Ie sens de dĂ©ïŹ‚le-
ment de la bande est appuyant sur la touche d-™a-
Vance ou de retour sans avoir a appuyer sur la
touche d-˜arrĂ©t. Les indicateurs de sens indiquent
le sens dc détilement de la bade («cu»).

Attentlm! -™i -˜i;

0 Pour une utilisation do I-™inversion rapids, uttiisez toujours one bti-˜mi-˜ayant

des section we claires de hande amoroc. «- .
u-™une bande prĂ©-enregistree est mitisĂ©e pour un enregistrĂ©-˜mmt uri
cycle d-™avmoe en return), la premierescwndedc I-™autre Em as In band:
as sera pas effaoée. . v . .

Effacez manuenemem cette section. .

O Pendant ta function d-˜inversiun rapine, aucun enrĂ©gisttemerrt rte s-˜et-˜l-™ec-

were pmdant 0,8 sewn-1c. i .

_ gr.
u Le selectem d-™inversion (IE9 SELEIT) u-˜a pas dielfel pendant lesilfonctions

de balayage d-™tntroduction et de recherche des bhncssonores. _
Le -œoerveau- du microprocesseur et les -œyeux- infrarouges du GX-R99 vous


l. Appuyez sur le sĂ©lecteur d-˜inversion (IE! ïŹlial) pour rĂ©gler
1: mode.

A : Indique que la bande ne peut dĂ©ïŹier que dons tin sens, scion
) Ia touche qui est enfonoée: soil (4 ), soil (> ).
B :Indique un cycle complet. La bande sera reproduitejusqu-™a

Ia ïŹn de la face 1. s-™inversera, Ia face 2 sets rewoduite. et la
bande s-˜arrĂ©terat

) C :Indique une reproduction a l-˜int-˜mi. La bandecontinuera it
s-™inverser et a Ă©tre reproduite jusqu-˜Ă© oe que ious changiez

Ia fonction,

1. Press the HEB/MUSE ( 0 1 button to standby for recording

2. Press the Rev, Selector to set the mode

A : Same as above only in recording mode

8: In this mode. the Akar GXVRQQ wrll record one complete

-˜-) 14 Appuyez sur la touche d-™enregistrement/paure ( I ) pour
_. passer nu mode d-™attente d-˜enregistrement.

cycle (side A and side B) then go into continuous playback
of the just recorded tape

Appuyez sur Ie sĂ©lecteur d-˜tnversion (IEV SElEll-˜) pour regler
Ie mode.

-˜- , t A 4 s
D A : Identrque a cr-dessus, mars sur le mode d enregsrrement.
B :

Sur ce mode, 1e GX-R99 Altai enregistrera un cycle oomplet

Auto Tape Tuning

The Auto Tape Tuning function which takes place automatical-
Iy whenever the Rec, button is depressed, produces the maxir
rnurn performance from any type of tape. The GX»R99 sets ope
timurn Elias, Equalization and Sensitivity for Normal. Chrome or
Metal position tapes-all within a few seconds. This assures
low distortion. high output,tlat frequency response. more accuV
rate meter readings and better Dolby NR tracking.

8qu erasing
Previously recorded rriusrc is erased as new recordings are made

However. to erase an entire tape, depress the amplitier-˜s input selector (AUX
or TAPE 2) whose input jacks are not connected and then depress the

REE/MUS-œ 0 land play (b ) buttons to start recording plank tape,


(face A at face B). puis se mettra en reproduoion continue
de in bande qui vient juste d'Ă©tre enregjstree.

Syntomsatron automathue de bande

La function de synwnisation automatique dc bante qui s-™et-˜fec-
tue automariquement Iorsque Ia touche d-˜enregistremcnt est en-
clenchĂ©e, donne Ies performances maximum aiec m-˜importe
quel type do bands. Le GX-R99 regle Ia polarisation, I-™Ă©galisatior et la sensibi-
lité optimales pour les bandes a position non-hale. chrome ou mm -tout oela
en quelques secondes. Ceci assure une {aible distorsion, une sort-˜e elevĂ©e, une
réponse en fréquence linéaire. des indications plus préciscs del'indicaleur et
un meilleur alignement Dolby NR.

Effacement total

La musique prĂ©cedemment enregistrĂ©e est etTace-™e lorsque de nruveaux enres
gistrements sont ctTectués.

Cependant, pour en-˜acer In bande enti-˜ere iI t-˜aut appuyer sur la electeur d-˜en-
tree de l-™ompliïŹcateur (AUX ou TAPE 23 dont les jacks d'entrĂ©e no sont pas
connectĂ©s, puis appuyer simultanĂ©ment sur les touches d-˜enegistrement/
panse ( I ) et de lecture (V) pour commencer l-™enregistrement.

oI-˜I-˜renI Ia facilite-™ absolue des operations d-˜enreg-˜strement clde reproduction.

Page 37

The Auto Monitor

What is an auto monitor
system '?

The independent recording and playback heads in
combinatdion with two independent ampgfilers (one
or recor ing and another for playbac ets you
listen to a recording as It is being made This is
called tape monitoring. By switching the tape monia
tor system during recording. you can compare the
just recorded music (TAPE position) to the source
music (SOURCE position), in this way you can make
sure that you have set the recording input levels cor-
rectly, The tape monitoring system of the GX-R99 is

rrr: mow

called -œauto monitor system". Beside letting you manually set the tape moni-
tor system, it also does it automatically. When the GXVRSS is recording. the
auto monitor system is set automaticallyto TAPE and during recording stands
by. it is set automatically to SOURCE.

There is no need for you to set the auto monitor system yoursell.

Recordlng Enregisttemcnt
Sou rce Result
Source Raullal

Encoder W Encoded tape
Encoder" Band: encode:

-˜) -) A Boostedsolt a -

WWW Sensuouxamplme



Loud saunas
Sous forts
sort sounds
Sum dull!

Systéme automatique
do contrt-˜iIe

Qu-™est-ce qu-™un systĂ©me
automatique de controls?


a Les tĂ©tss indĂ©pendantes rt-˜emegistrement at de reproduction
combinĂ©es i deux ampliïŹcaleurs independants (l'un pourl-˜m-
registrement. t'autre pour in reproduction), yous pennant-rt
d-˜Ă©couter un enregistrsment pendant qu-˜il s-™eïŹ‚moe. Coolest
appelé controle de bands. En commutnnt le system: de mn-
trĂ©le do band: pendant l-™enregistrcmenl, vouspouvez compo,
rer la musiquc qui Vienl juste d'Ă©lre enrog-˜strĂ©e (position
hands-TAPE) A la musique do source (position SOURCE).
Cette me'lhode vous permet de vous murer quc vous nvez
correctemsnt rĂ©glĂ© les nivenux d'entrĂ©e d-˜enrdgistremenl. Le
systems do control: (to bands du GX-R99 est appele' -œsystems
automotique-˜ds controls". Non sculement il vous permsi dc ro'gler manuoliement 1e Sysr-
téme dc contrélz tie bands, mais ll I: fail également automatiquement. Lotsque 1e GX-R99
AkïŹ‚i enmgislre, 1: systems auwmalique cl: oontrĂ©le est aulomatiquement rĂ©glĂ© sur TAPE,
et pendant l-˜ntlu'tte d-˜enregistrement. il est Iutomltiquement rĂ©glĂ© stir SOURCE.
Vous n-˜avez donD Pas min derĂ©sler yous-mime le system automatique decontrïŹle.

Playback Reproduction

7306 Result

Band: RĂ©sultat
Encodcdtape W Denoder
Hand: encodes Loud sounds WWW Low: iounu.

-@ a «x- W:
Boosted sort sounds W soitscunqs W

Sons doux amphïŹĂ©s Sons doux raw-s ,

Tape nurse Lowered

tape no se
E i do b d
"" -˜" -˜ Bruitdcbandedimlnue

1 .What is Dolby n0ise reduction (NR) system ?
When you record without Dolby NR system. you can't hear the solt sounds
very clearly because they are masked by noise added by the tape during
recording The Dolby NR system reduces this annoying tape noise.

The Dolby NR encoder circuit boosts the low-level signals (soft sounds)
during recording and at playback.the Dolby NR decoder lowers the low-level
signals by exactly the same amount to restore the low-level Signals to their
original levels At the same timetape noise is lowered bythe same amount,
The result is reduction only in the unwanted tape noise,

2. What is the difference between Dolby B-type
and C-type NR system?
e C

B-type: This ist onventional Dolby NR system. It boosts or lowers the
low-level signals at high lrequencies only (more than 5 kHz) and reduces
tape noise by todB.

C-type: Compared to the Dolby B, it operates at lower frequencies (from
_500 Hz) for uniform noise reduction across the audible spectrum. Tape noise
is reduced by as much as 20dB.

Therelore. you get better results with Dolby C. however when you are playing
back tapes recorded with the conventional Dolby NR system. set the selector
to Dolby B, Don-˜t lorget to always set the ltltllv Ill system before recording or
playing back a tape.

3. What is double process Dolby NR system?

In the conventional Dolby NR system, one circuit acts bot as an encoder
and as a decoder and is swrtched to become either one according to the
need. In the double process Dolby NR system, there is an encoder circuit in
the recording amplilier section and a decoder in the playback amplifier sec
tion. The double process Dolby NR system is used in cassette decks with 3
independent heads (recording, playback and erase), Therefore when record»
mg with Dolby NR. you can immediately confirm the eflect ol the Dolby NR
system by monitoring thejust recorded music.

' -œDolby" and the doubleD symbol are trademarks of Dolby Laboratories
Licensing Corporation (Manulactured under license lrom Dolby Licens-
ing Corporation.)

Syst-˜eme Dollty till

1. Qu-™est-ce que le systĂ©me ole rĂ©tluction de bruit
(llll) Dolby?

Lotsque vous emegistrez sans systems Dolby NR. Von; ne pouvez pas enlanltre Iris Claire-
ment 1%: sons doux Dame qu-˜ils soul masquĂ©s per lo bruit ajoutĂ© par la band: pmdantl'enrcv
gimmenl. Le systéme Dolby NR reduit oe bruit dc bande ennuyeux.

Le circull encodeur Dolby NR ampliïŹe les signaux die l-˜aible nivcau (sons ibux) pendant
l'enreg-˜su'ement, cl, a la reproduction, lc dĂ©oodeur Dolby NR redul't les iiguux de faible
nivenu d'exaclement la méme quantilé pour nmener court-oi i leurs niveauiloriginnux. Lo
bruit tie bands est en méme temps diminué do In mime qmntité. Scul le brur. tie bands in-
de'sirahle est don): réduit,

2. Quelle est la difference entre les systémes Dolliy
lilttypeBett eC?

Type-B: C ïŹl le systĂ©me o yNR conventionnel, I] n-˜ampliïŹe ou l're reduitles Signnux de
ÂŁ313; niveau qn-˜aux hautes irĂ©quennes (supĂ©riemes a 5 kHI), el redui! Ie brill tie band: do

-c-˜ Compare nu Dolby a, il an alliance Stir dos frĂ©quenoes plus nurses opanlr de 500
Hz pour une rĂ©duction uniform: du bruit sur tout to spec-œ: audible. Le hrul ae halide est
rĂ©duitdejusqu-˜n 20 on.

Vous omens: done a: meillcurs résultats ave: Dolby c; «mam, lorsque rous mpmdur-
sez ties halides enregistrées avec le sysléme Dolby NR conventinnncl, réglrz 1e iélwteur
sur Dolby a, N-™oubliez pas die toujtmrs tester le system nut Ill avant d'encgislrer ou de
teproduire une bands.

3. Qu-™est-ce que le systĂ©me Dolby NR double

procéde ?
Dans Ie systĂ©ms Dolby NR conventimnel. un settl circuit agit ii la this on tantqu -˜enoodzur
er dĂ©codeur. at il est commute pour devenir l-˜un dz cos deux elements seloii [as bsooins.
Dans le systeme Dolby NR double procĂ©dĂ©, i] y a un circuit enuodeur dens 1! Sutton ampliïŹ-
cateur d-˜enrcgistrement et un circuit dĂ©oodsur dans In section ampliïŹcatemde reproduc,
lion. Le sysleme Dolby NR double procédé at utilise dans les mamétocaoettcs ayant 3
tĂ©tos indĂ©pendantes (emegistrcment, rsproduci-˜ et armament). Lars d'm amsgistre-
merit am Dolby NR, ll you: extdmtcpos 'ble do ven r immĂ©d'mement I'GïŹ‚ild usystĂ©me
Dolby NR en levrpduisant la musique qu. vientjuste d elre enregistrée.
-˜ Dolby et le symbol: Double D sont dos marques dĂ©posĂ©es do Dolby Loturalon'es Li-
censing Corporation. (Fabriqné sous licence do Dolby Laboratoris Licensing

Page 56

PRE AMP ADJUSTMENT CHART (for more detail, see 7-2-1 to 7-2-3)

Adjustment Test Tape & Adjustment
Step Item Mode Supply Signal Point Result
Connect INPUT VR4 (L) TPI (L)
1 DC 33'3-œ-œ STOP PIN of P30 with GND VR4 (R) TPI (R) o t 100 mV DC
333 Hz 0 VU Tape VRS (L)
FWD PLAY (315 Hz 0 VU Tape) VRS (R) LINE OUT
2 RB Level -6.l 10.1dBm
333 Hz 0 VU Tape -˜ (-5.5 1 0.1 dBm)
REV PLAY (315 Hz 0 W Tape) ConïŹrmation
VR6 (L)
3 PB EQ FWD PLAY 10 kHz RE E0 Tape VR6 (R) 7205 2 02 dBm
REV PLAY 10 kHz P.B EQ Tape ConïŹrmation -20.5 t 20 dBm
4 METER TAPE MONITOR 1 kHz LINE IN VR3 (L) +1 V'U indication on VU
Sensitivity SOURCE (-5.2 dBm LINE OUT) VR3 (R) METER Display
315 Hz 0 vu Tape VR2 (L) -5.5 t 0.3 dBm
5 Dolby Decoder FWD PLAY VR2 (R) When Dolby ON
(333 Hz 0 VU Tape) (-6.1 2 0.3 dBm)
6 MPX Filter REC 19 kHz LlNE IN FL2 (L) MIN
FLZ (R) When MPX sw ON
. REC/PLAY No Signal Input LINE OUT
7 3:313? t METAL Tape PM (L) MIN
8 MAGS, 3"- REC/PLAY No Signal Input VL1 (L) MIN
' METAL Tape VL1 (R)

(TUNING P.C board is disconnectable from
METERP.C board)

1) DC Balance
a. Remove connector of P30 (PB HEAD Connector)
13. Connect INPUT SIGNAL PIN of P30 Pin @, Q4)
to GND.
0. Adjust VR4 so that the voltage of TPl will be
0 i 100 mV DC.
2) PB Level
3. FWD Play Back 333 Hz (AT-750773) or 315 HZ
(AT-750773) PB level adjustment tape and adjust
VRS so that the LINE OUT level will be 333 HZ
to -6.1 t 0.1dBm or 315 Hz to -5.5 i 0.1 dBm.
b. REV Play Back 333 Hz or 315 Hz PB level adjust-
ment tape and confirm so that the LINE OUT
level will be -6.] i 0.6 dBm (333 Hz) or -5.5
x 0.6 dBm (315 Hz).
3) PB E0
3. FWD Play Back 10 kHz PB EQ adjustment tape
(AT-750778) and adjust VR6 so that the LINE
OUT level will be -20.5 i 0.2 dBm.
b. REV Play Back 10 kHz PB EQ adjustment tape
and conïŹrm so that the LINE OUT level will
be -20.5 i 2.0 dBm.

a. With the monitor SW to SOURCE and the meter


SW to VU, Supply lkHz to LINE IN, a IkHz
signal -5.2 dBm at LINE OUT.
b. Adjust VR3 so that the +1 VU.


1) Dolby Decoder Adjustment

a. FWD Playback 315 Hz PB level adjustment tape

b. Adjust VR2 so that the LINE OUT level will be
-5.5 i 03 dBm when Dolby ON. (At 333 Hz PB
level adjustment tape, LINE OUT level will be
-6.1 i 0.3 dBm)

2) MPX Filter adjustment

2. Set a blank tape and set to REC/PLAY mode.

b. MPX ïŹlter SW OFF, input a signal of 19 kHz from

c. Adjust FLZ so that the LINE OUT level will be at
minimum when MPX ïŹlter SW is turned ON.

3) BIAS Filter Adjustment

a. Set a metal tape and set to REC/PLAY (0r REC/

b. Adjust PM so that the LINE OUT level will be at
minimum when the recording volume is set to
MAX and the monitor SW to SOURCE.

c. Set a metal tape and set to REC/PLAY mode.

(1. Adjust VL1 so that the LINE OUT level will be at
minimum when the monitor SW is set to TAPE.