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Technics RS-B205 Service Manual

Technics RS-B205
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Bees
740he)
™@
MEASUREMENT
AND
ADJUSTMENT
METHODES
VR3,
4
Overall
gain
adj.
S
VR3
=VR2
VR301,
302
Bias
current
adj.
<4
TP1
Measurement
Condition
einput
level
controls;
Maximum
¢
Balance
controls;
Center
eTape
select
switch;
Normal
Dolby
NR
switch;
Out
Measuring
instrument
©
EVM
(Electronic
Voltmeter)
Oscilloscope
¢
Digital
frequency
counter
©
AF
oscillator
Test
tape
¢Head
azimuth
adjustment
(8kHz,
—20dB);
QZZCFM
Tape
speed
adjustment
(3kHz,
—10dB);
Q2ZCWAT
*
Playback
frequency
responce
(315Hz,
12.5kHz,
10
kHz,
8kHz,
4kHz,
1kHz,
250Hz,
125Hz,
63Hz,
—20dB);
QZZCFM
Head
azimuth
adjustment
Tape
speed
adjustment
VR
VR1,
2
7
Playback
gain
adj.
(Motor)
TP2
¢Make
sure
heads
are
clean
Make
sure
capstan
and
pressure
roller
are
clean.
e
Judgeable
room
temperature
20+5°C
(68+9°F)
e
ATT
(Attenuator)
¢DC
voltmeter
e
Resistor
(600Q)
¢
Playback
gain
adjustment
(315Hz,
0dB);
QZZCFM
¢
Overall
frequency
response,
Overall
gain
adjustment
«Normal
reference
blank
tape;
QZZCRA
*
CrO,
reference
blank
tape;
QZZCRX
¢
Metal
reference
blank
tape;
QZZCRZ
1.
Test
equipment
connection
is
shown
in
*od/Playback
Head
Fig.
1.
2.
Playback
the
azimuth
adjusted
part
(8kHz,
—20dB)
of
the
test
tape
(QZZCFM)
and
regulate
the
angle
adjusting
screw
so
that
the
outputs
of
L-CH
and
R-CH
are
maximized.
(When
the
adjusting
positions
are
different
with
L-CH
and
R-CH,
find
a
position
where
the
Azimuth
Screw
Fig.
2
outputs
of
L-CH
and
R-CH
are
balanced,
and
then
make
the
adjustment.)
.
At
the
same
time,
draw
a
lissajous
waveform
and
eliminate
phase
deflection.
Tape
speed
adjustment
1.
Test
equipment
connection
is
shown
in
Fig.
3.
2.
Playback
the
middle
part
of
the
test
tape
(QZZCWAT).
3.
Adjust
the
VR
in
the
motor
so
that
the
output
is
within
the
standard.
Standard
value:
3000+
20Hz
Playback
frequency
response
.
Test
equipment
connection
is
shown
in
Fig.
4.
Digital
frequency
counter
.
Playback
the
playback
frequency
response
part
(315Hz,
12.5kHz~63
kHz,
—20dB)
of
the
test
tape
(QZZCFM).
.
Chech
that
the
frequency
is
within
the
range
shown
in
Fig.
5
for
both
L-CH
and
R-CH.
LINE
OUT
SOHz
100Hz
200Hz
S500Hz
1kHz
2kHz
5kHz
10kHz
Fig.
5
Playback
gain
adjustment
1.
Test
equipment
connection
is
shown
in
Fig.
4.
2.
Playback
the
playback
gain
adjusted
part
(315Hz,
OdB)
of
the
test
tape
(QZZCFM).
3.
Adjust
VR1,
(L-CH)
{VR2
(R-CH)}
so
that
the
output
is
within
the
standard.
Standard
value:
0.4+.0.5dB
(0.02V)
Bias
current
adjustment
1.
Test
equipment
connection
is
shown
in
Fig.
6.
2.
Set
the
tape
selector
switch
to
the
normal
position.
3.
Insert
the
normal
tape.
4.
Press
the
record
and
pause
buttons.
5.
Minimize
the
input
level
control
and
adjust
VR301
(L-CH)
{VR302
(R-CH)}
so
that
the
output
between
TP1
(L-CH)
{TP2
(R-CH)}
and
ground
is
within
the
standard.
.
After
that
check
in
the
same
way
as
for
CrO,
and
metal
tape.
9V
(Normal)
Reference
value:
14V
(CrO.)
17
V
(Metal)
Overall
frequency
response
.
Test
equipment
connection
is
shown
in
Fig.
7.
LINE
IN
LINE
OUT
.
Set
the
tape
selector
switch
to
the
normal
position.
.
Set
a
normal
blank
tape
(QZZCRA)
and
record
by
applying
oF
=
signal
(50Hz,
100Hz,
200Hz,
500Hz,
1kHz,
4kHz,
8kHz
and
&
HO
00
10kHz),
20dB
attenuated
from
the
reference
input
level
signal
“*
»sctlator
(1kHz,
—24dB).
.
Playback
the
signal
recorded
in
step
3,
and
check
that
the
level
of
each
output
frequency
is
within
the
range
shown
in
Fig.
8
in
comparison
with
the
reference
frequency
(1kHz).
.
If
it
is
not
within
the
standard
range,
adjust
the
bias
current
by
VR301
(L-CH)
{VR302
(R-CH)}
so
that
the
frequency
level
is
within
the
standard.
«
Level
up
in
high
frequency
range
Increase
the
bias
current.
*
Level
down
in
high
frequency
range
Decrease
the
bias
current.
.
After
that
increase
the
signal
recorded
on
CrO,
blank
tape
(QZZCRX)
and
metal
blank
tape
(QZZCRZ)
up
to
12.5kHz
and
adjust
in
the
same
way
as
mentioned
above
and
check
that
the
frequency
level
is
within
the
range
shown
in
Fig.
9.
+f
+468
+208
0dB
—20B
40B
60B
63Hz
100Hz
200Hz:
500Hz2
1kHz
2kHz 4kH2
8kHz
12.5kHzZ
315Hz
Fig.
8
Fig.
9
SOHz
100HzZ
200Hz
SOOHZ
1kHz
2kHz2
5SkHz
10kHz
Overall
gain
adjustment
.
Test
equipment
connection
is
shown
in
Fig.
7.
.
Set the
tape
selector
switch
to
the
normal
position.
.
Set
a
normal
blank
tape
(QZZCRA)
and
apply
the
reference
input
level
signal
(1kHz,
—24dB)
in
record
pause
mode.
.
Adjust
the
output
0.42V
by
attenuator
and
then
record.
.
Playback
the
signal
recorded
in
step
3,
and
check
that
the
output
is
within
the
standard.
.
If
it
is
not
within
the
standard,
adjust
VR3
(L-CH)
{VR4
(R-CH)}
and
repeat
the
step
(2),
(3)
and
(4)
until
the
output
is
within
the
standard.
Standard
value:
0.4V+0.05V

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Technics RS-B205 Specifications

General IconGeneral
BrandTechnics
ModelRS-B205
CategoryCassette Player
LanguageEnglish

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