Akai 4000DS Service Manual page 13

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
1XA
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.