Amplifier Adjustments; Vu Meter Sensitivity Adjustment - Akai GX-225D Manual

Vil. AMPLIFIER ADJUSTMENTS
RIGHT CH. VU METER SENSITIVITY ADJ. VR202b SKB
RIGHT CH. P.B.LEVEL ADJ. VR20ib 20KB
RIGHT CH, REC. LEVEL ADJ. VR30Ilb 20KB
LEFT CH. VU METER SENSITIVITY ADJ. VR202 5KB8
LEFT CH. PB. LEVEL ADJ. VR20I 20KB
LEFT CH. REC, LEVEL ADJ. VR30! 20KB
LEFT CH. REC. BIAS VOLTAGE ADJ. TCSOS 7OP
RIGHT CH, REC. BIAS VOLTAGE ADJ. TCS5O06 70P
® : PLAYBACK AMP, RC, BOARD MS-5022
@® ; RECORDING AMP. P.C. BOARD MS-5023
© ; OSCILLATOR P.Cc. BOARD MS-5025
GX-225D High
Line Sensitivity
V.T.V.M.
output
Fig. 21
_—
. PLAYBACK OUTPUT LEVEL ADJUSTMENT
1) Connect a high sensitivity V.T.V.M. to the line
output terminals.
2) Set both the Tape Speed Switch and Equalizer
Switch to 7-1/2 ips (19 cm/sec.), depress STEREO
Track Selector and set the Monitor Switch to
TAPE position.
3) In case of model GX-225D, set Noise Reduction
Switch to OFF position.
4) Playback a 250 Hz ''0" VU pre-recorded test tape.
5) Adjust P.B. Amp. P.C. Board playback level
adjustment semi-fixed resistors VR201 20 kB
(Left Channel) and VR20lb 20kB (Right
Channel) shown in Fig. 20 to obtain a High
Sensitivity V.T.V.M. indication of 4 dB (1.228 V)
Fig. 20
2. VU METER SENSITIVITY ADJUSTMENT
After the playback output level adjustment has
been completed, adjust P.B. Amp. P.C. Board VU
meter sensitivity adjustment semi-fixed resistors
VR202 5kB (Left Channel) and VR202b 5 kB
(Right Channel) shown in Fig. 20 to obtain a VU
meter indication of "0" VU on both channels.
3. HIGH FREQUENCY DEVIATION CHECK
1) Between Channels
When an 8,000Hz 3-3/4 ips Ampex Alignment
test tape is played back, check to confirm that the
difference in high range output level between the
left and right channel is within 2 dB.
2) Between FWD and REV Playback
Playback and Alignment test tape and check to
confirm that the difference in high range level
output between FWD and Reverse playback mode
is within 3 dB.
3) If Items 1) and 2) above are not within specifica-
tions, repeat Head Azimuth Alignment adjust-
ment. '
18