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—
Increase the frequency to 10 kHz.
— The phase difference should be smaller than 45°
if necessary, readjust with screw C.
14. Adjustment of channel equality, indicator reading and
recording amplifier
— Set recorder in position: 9.5 - ST - SOURCE.
— Apply a signal of 330 Hz, 500 mV to BU1 (BU101).
—
LINE-OUT control at maximum.
— Adjust for 1 V output voltage on BU104 with
recording level control for right-hand channel.
'Set recording level control for left-hand channel to
same position as for right-hand channel and adjust for
1 V output voitage on BU4 with R214.
—
Adjust for a 0 dB indicator reading with R78 (R178).
—
Insert a reference tape (e.g. BASF C264Z).
—
Set recorder in position: SOURCE - REC - PLAY.
—
Apply a 330 Hz signal until
1 V appears on LINE-
output BU4 (BU104) (indicator reading 0 dB).
—
Set recorder in position TAPE CUEING.
— Adjust for 1 V voltage on BU4 (BU104) with R63
(R163) (indicator reading 0 dB).
15. Adjustment of bias, check of overall frequency
response and distortion
—
In case of a correct adjustment of the bias, a compro-
mise must be found between frequency response and
distortion.
The target value is 8 mV {across R61, R161), and is
adjustable with R90, R190.
— Set recorder in position: 19 - ST - TAPE CUEING -
REC - PLAY.
—
Insert a frequency tape (BASF C264Z).
—
The frequency response should be measured at —26 dB.
The frequencies 35 Hz and 25 kHz should be within
7 dB.
The frequencies between 250 Hz and 6300 Hz should
be within 5 dB.
The reference point is at 1 kHz.
— The distortion measured at 0 dB, should be smaller
than 3 %.
If the high frequencies are too much attenuated, the
bias current will be too high. If the high frequencies are
too strong and/or if distortion is audible, the bias
current will be too low.
This is adjustable with R90/R190.
—
If R90/R190 has to be adjusted, repeat the frequency
response measurement.
|
. LUBRICATING INSTRUCTIONS
Mobil oil SHC 634 — 4822 390 10074.
Capstan bearings item numbers 238, 324.
Shell Alvania 2 — 4822 389 10001.
Sliding surfaces of item numbers 266, 296, 309, 329,
526.
Silicone grease medium 300 — 4822 390 20031
Left-hand shaft of item number 309.
Heavy medium DTE — 4822 390 10065
Right-hand shaft of item number 309.
24 08BI2
21407812
Q@
@
B
C
22713A12
Fig. 5
Fig. 7
21410B12
Fig. 9
CS 74 684
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