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ADJUSTMENT
& PERFORMANCE
OF
ELECTRICAL
PARTS
(1)
Measuring Instruments
In order to test and adjust electrical
parts, the following
instruments
are required:
1.
Tester
2.
Vacuum
Tube
Voltage Meter
3.
Low
Frequency
Oscillator
4.
Attenuator
5.
Oscilloscope
6.
Standard
Recording
Tape
(2)
Adjustment of Standard Recording Level
Arrangement
of Tape
Recorder.
(Switch
position "REC",
Volume Maximum)
Attenuator
Tape recorder
( y
of
1V=- constant
Low frequency
'oscillator
Adjust the semi-fixed
VRy
(5 KQ)
so that
the
VU
meter
will
register
0 db
at
the
Microphone Input terminal at—71 db,
(3)
Oscillation Bias Current
Bias
current
during
the recording
Power
Input:
is measured
at
both
ends of R42.
Adjustment
is made
by semi-fixed
VRg
so
that the voltage will register 7mV.
7mV
R42
RP head
(4)
Adjustment of Head Angle (9.5 cm/sec. at Playback)
Use standard
recording
tape
of 5000
c/s
and
adjust
the
screw for angle
adjustment
so
that
the
power
output
will
reach maximum.
a
tope width
0.2~-0.3mm
lope center
(5)
Indication
of Power
Voltage.
(Battery
Voltage
Indication)
Connect
6.5 V
power
to battery
terminals,
put the machine
in "PLAY"
position.
When
VR MIN. adjust the semi-fixed
VR4
(50K)
so
that
the
indicator
will
point
to
the
same
position as OVU.
(6)
Voltage and Current Value of each
part.
Gain
Distribution and Frenquency
Response
of each stage.
+
Gik
RI
Tr5 Teé
béddi
leg
1.
Voltage
value
of each
part.
2.
Current value
of each
part.
auge
ay-|
Recor-
|'Tester
Gauge
ay-|
Recor-
|Test
point
back | ding
|range
point
back | ae
range
A(yv) {15.7
14.5
5
A
(mA)
Biv) | 6.8
6.5
25
B (mA)
Civ) | 60
|
57
25 |
|Tr-Te (uA)
7
Tr-8,E(v)
| 8.8
8.3
25
Tr-2,e
(nA)
Tr-7,C(v)
| ~~
8.0
25
Tr-3,e
(uA)
Tr-4,C(v)
| 7.0
6.8
25
Tr-4,e (nA)
Tr-3,C(v) | 5.4
5.0
|
25
Tr-7,e (mA)|
~~ | 42.5
| 100
"Tr-2,C(v) | 2.3
2.4
10
ob
ee
"Tr-1,C(v) | 21
2.3
10
Tr-7,C(W) | >7 |
10
~|_10
Tr-4e(v)
| 20 [| 1.9
10
Tr-3,e(v) | 1.8
17
10
Tr-2,e(v)
| 1.5
1.5
10
Recording
bias Current.
Erasing
Current.
E head
RP head
10ohms
l4mA
5.
Gain Distribution and Frequency Response of each stage.
Tr-1(c)
| Ir2(e)
| Iro(c)
| Tr-4(c) | OPT 2
OPT 3
105
:
c/s
mv
mv
|
mv
v |
v
v
mv
|
100
5.0
49.0
17.0
1800
1.7
el
eae
sss-
ae
fs
|
ee
Input
[K
1.5
1L5
15
500
0.5
level
:
Playback
7
7
:
<
=
—;
70db
7K
13
9.5
24
245
0.3
-
|
I
a
=
100
105
|
20
2.3
205
ia
16.0
0.4
!
~
a
a
~
Input
|
F
1K
ll
|
25
0.5
105
|
18.0
0.45
level
Recording
=
|
en
_70db
|
ai
1.0
2.15
4.3
400
Se
23.0
1.9
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