Werbung
ELECTRICAL MEASUREMENTS AND ADJUSTMENTS
General conditions
The following general conditions apply to the electrical
measurements and adjustments, unless explicity stated
otherwise.
—
Mains voltage 220 V + 5%, 50 Hz
—
Ambient temperature 20 to 25°C
—
Dolby/MPX switch SK3 off
—
Tape selector: Cr SK5
~
Volume control recording level 3122: max.
—
The voltages have been measured relative to earth.
Recorder in
position
Playback
SBC419Cr
|PLAY
speed
3150 Hz
Azimuth
SBC419Cr
PLAY
R/P head
10 kHz
K1-K101
Playback
SBC419Cr
|PLAY
sensitivity
315 Hz-0 dB
+
Indicators
Adjustment ; Cassette
Apply signal to
Recording
sensitivity
BIAS
40 Hz-6.3 kHz
10 KHz-12 kHz
13 kHz-14 kHz
f.osc.
19/85 kHz
Arbitrary
REC
suppression | cassette
DOLBY/MPX
19 kHz, to
BU4
(BU5)
(same input
(BU5)
(same input
voltage)
—
The measurements and adjustments are related to the left-
hand channel.
The corresponding test points and adjusting elements for
the right-hand channel are given in brackets.
Required test equipment and test cassettes
—
LF generator
—
AC millivoltmeter (mV-meter)
—
Wow-and-flutter-meter
—
Universal test cassette SBC419Cr - 4822 397 30069
—
Multimeter
—
Frequency counter
Measure on | Read on
Adjust with
Adjust to
BU6
(BU7)
.BU6
(BU7)
Wow-and-
3904
*b
flutter
meter
(Filter on)
*
mV-meter
c
Max. output
Left hand
screw of
K1-K101
BU6
| mV-meter
3128
650 mV
(BU7)
(3129)
U404
3238
+ 1dB
(3239)
Playback
SBC419Cr
|PLAY
BU6
mV-meter
See graph Fig. 6
frequency
40Hz ;250Hz:;
(BU7)
frequency res-
response
6.3 kHz;
ponse
12.5 kHz
Target value } Arbitrary
MP1
mV-meter
a
9.6 mV
BIAS
cassette
(MP101)
a
(10 mV)
BU6
mvV-meter
LF-Generator
290 mV
(BU7)
Disable the bias by removing 3224
MP1
(MP101
m\V-meter
3218
:
0.9 mV
)
(3219)
Connect 3224 make a recording and play it back
BU6
(BU7)
MP1
(MP101)
au
(BU7)
290 mV
mV-meter
*e
mV-meter
3220
9.6
dite target
(3221)
(10 mV) Jvalue
i F-generator
29 mV
Record a number of frequencies
with the same input voltage
(BU7)
ee) cS
© >)
(BU7)
BU6
(BU7)
w => a = ae
mH
s°
and play them back
mV-meter
See graph Fig. 7
if necessary repeat
BIAS adjustment
"f
Frequency
5106
85 kHz
counter
LF generator
775 mV
mV-meter
5102
<= 25 mV
(5103)
19 kHz part
mV-meter
5102
Min output
(5103)
< 4.35 mV
85 kHz part
Werbung
