Akai 4000DS Mk-II Service Manual

VI. AMPLIFIER ADJUSTMENTS
Fig. 12
LEFT MIC. VR.
VR-I
LEFT LINE VR.
VR- I
RIGHT MIC. VR.
VR-2
EQUALIZER SW.
SW2
RIGHT LINE VR
VR-2
MONITOR SW
SW 4
TAPE SELECTOR SW.
SW 3 Fig. 14
H
<MLEFT RB. LEVEL
| $ VR-2 (£3j
'right pb. level|
vR - 2b €3
VR-.b|Q
[RIGHT REC. LEVE
I* I
vr -'$C3
JLEFT REC. LEVEL j_
5
Fig. 13
1. PLAYBACK LEVEL ADJUSTMENT
(See Figs. 12, 13, and 14)
1) Set the monitor switch to “TAPE” position and
Equalizer switch to 7 Yi ips.
2) Connect a High Sensitivity V.T.V.M. to the line
output.
3) Playback a 250 Hz pre-recorded test tape at 1 X A
ips., and adjust semi-fixed resistor VR-2 and VR-
2b (20 kB) to obtain a 4 dB P.B. level. (VU meter
indicates “0” VU)
Recording Amplifier Adjustment should be made
only after Head Adjustments and Playback Ampli¬
fier Adjustments have been made.
2. RECORDING LEVEL ADJUSTMENT
(See Figs. 12, 13, and 14)
1) Set the monitor switch to “TAPE” position and
Equalizer switch to 714 ips.
2) Connect an Audio Frequency Oscillator to the line
input and High Sensitivity V.T.V.M. to the line
output.
3) Load a Scotch-111 blank tape and set recorder to
“REC” mode.
4) Supply a 1,000 Hz sine wave from an Audio
Frequency Oscillator and adjust the line recording
level control volumes (VR-1 and VR-2 50 kB)
until the line output level reaches 4 dB. (VU meter
indicates “O” VU)
5) Set the monitor switch to “SOURCE” position.
6) Adjust semi-fixed resistor VR-1 and VR-lb (2 kB)
to obtain 4 dB recording level. (VU meter in¬
dicates “O” VU)
7) Repeat 2 times in the same way as indicated in
Items 4) to 6) above.

Akai 4000DS Mk-II Specifications

General

Type	Reel to Reel
Track System	4-track, 2-channel, stereo/monaural system
Signal to Noise Ratio	50dB
Reel Size	Up to 7 inch reel
Total Harmonic Distortion	1.5%
Output	0.775V (line)
Tape Speed	3.75 & 7.5 ips
Heads	1 x erase
Input Sensitivity	50mV (line)
Semiconductors	6 x Transistors
Inputs	Line
Outputs	Line