Akai GX-4000D Service Manual

Vil. AMPLIFIER ADJUSTMENT
HIGH SENSITIVITY
ene
AC
VOLTMETER
OSCILLATOR
OUT IN
FREQJENCY
COUNTER
Fig. 11 Instruments Connection
1. MODEL GX-4000D
‘ee
®)
VES 23mH
REC AMP BIAS FILT|
CtaRT SAS FER
YRE_5KB
\U METER SENS
(RIGHT)
VR4 5KB
REC LEVEL
1
2, 23 ni
AMP BIAS FILT
IGHT) 6 FireR
VL4 23m
REC AMP BIA!
igus PUTER RESPONSE
wag
7
a
ey
raton
me
{RIGHT} Be LeveL
VU to WL
Adjust from the oppose sae
(@)
Fig. 12. Amp P.C Board LE-5801A (GX-4000D)
Step
|
Adjustment
Test
Tape
\
Adjustment
Item
{Supply
Signal
Mode
Point
Result
Remarks
Playback
|
700
H
L
Level
|
7-1/2
-
VR2
50
kB(L)
haar
i
;
f
2
ied
+
Monitor
Switch
to
Adjustment
eae
a
vrs
50
BR)
proce
“TAPE
:
i
|
|
|
(0.778V)
APE”.
VU
Meter
700
Hz
i
|
2
Sensitivity
7-1/2
ips
pray
|
WR3
5
KB(L)
|
OVU
Adjustment
|
Test
Tape
VR6
5S
KB(R)
indication
|
SCOTCH
#2
re
Frequency
tape
1,000
.
(Bae
3
|
Response
ipod
Ha
|
RECE
|
MCL
ZORL)
Py
GGL.
4
|
SARC
SRE
ate
ee
aeer:
Adjustment
-20
VU
pre
See
sR
|
aa
ica
ine
recording
4
poets
ci
SCOTCH
#211
ood
tape
1,000Hz
|
REC/
|
REC
Volume
i
oe
Set
Monitor
Switch
to
’
ecording
|
0
VU
recording
PLAY
|
(VRB
SOKA)
|
775yy_
|
“TAPE”
eve.
:
Adjustment
SCOTCH
#211
[
REC/
|
VRI
Sk
O.dbm
tape
1,000
Hz
B(L)
2
Set
M
i
4
;
+0.5
dB
onitor
Switch
to
OVUrecording
|
PEAY]
VR4
SBR)
|g
azsyy_|
“SOURCE™
oe
an
ae
5
re
cant
5
Adjustment
Test
Tape
Adjustment
|
Step
lied
Supply
Signal
|
moi
Paint
Result
Remarks
os
ae
Distortion
1,000
Hz
5
Factor
0
VU
REC/
Less
than
(Refer
to
NOTE
5)
‘
2
A
PLAY
1.0%
j]
eA
recording
a
PB
Amp
Bias
100
kHz
Minimum
Set
Monitor
Switch
to
6
Filter
from
an
REC
as
=
aes
AC
Voltmeter
|
“TAPE”.
Adjustment
oscillator
7
m™
indication
(Refer
to
NOTES
6,
7)
T
.
:
REC
Amp
Bias
100
kHz
Minimum
Set
Monitor
Switch
to
7
Filter
from
an
REC
bot
5
aay
AC
Voltmeter
|
to
“SOURCE”.
Adjustment
oscillator
"
indication
(Refer
to
NOTES
6,
7)
|
=e
ack
os
a
Chart-1
NOTES:
1.
Output
Level
Control
should
be
at
maximum.
2
3
4
5
6
d,
.
Except
for
Step
3,
set
tape
speed
to
7-1/2
ips.
.
Set
tape
selector
to
Low
Noise
position.
.
(L)
=
Left
Channel,
(R)=
Right
Channel.
_
If
it
does
not
comply
with
the
specifications,
repeat
Steps
3,
4
and
re-adjust.
.
Unless
the
core
is
moved
intentionally
this
adjustment
is
not
necessary.
.
Adjust
the
oscillator’s
frequency
to
give
a
frequency
counter
reading
of
100
kHz.

Akai GX-4000D Specifications

General

Track System	4-track, 2-channel, stereo/monaural system
Reel Size	Up to 7 inch reel
Tape Speeds	3 3⁄4 7 1⁄2 ips
Frequency Response	30Hz to 24kHz (7 1⁄2 ips)
Type	Reel to Reel
Heads	1 x erase
Motor	1 x capstan, 1 x reel
Wow and Flutter	0.08% (7.5 ips)
Output	0.775V (line)
Input	70mV (line)
Inputs	Line
Outputs	Line