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10.2
ELECTRICAL
ADJUSTMENTS
=
Before
commencing
any
electrical
adjustments,
make
sure the following checked/completed.
1.
2
3.
37
All mechanical
adjustments
must
have been
completed.
The heads must be clean and demagnetized.
Connect
a 50kQ
(47kQ
~
52kQ)
dummy
resistance to the OUTPUT
terminal with 0dB
= 1V during level measurements.
Use the specified tapes for each adjustment.
Although test tapes have both A and B sides,
only use side A where the label is attached.
STD-331B:
Playback adjustment
STD-608A:
NORMAL blank tape
STD-603:
CrO2 blank tape
STD-604:
METAL blank tape
Prepare
the following
measuring
equipment.
AC millivoltmeter, audio generator, attenuator,
oscilloscope.
Adjust
both
left
and
right channels
unless
otherwise specified.
And
unless
indicated
otherwise,
leave
the
DOLBY
NR switch in the OFF position.
Let the set warm up for at least a few minutes
before
commencing
adjustments.
And
before
commencing
the
record/playback
frequency
response
adjustment,
let the
set "age"
for
three to five minutes.
Always adjust the set in the given adjustments
order. If the order is changed, proper adjust-
ment will not be possible, and this may result
in loss of performane.
Adjustment Procedure
Deck A
1.
Head azimuth adjustment
2.
Playback equalizer adjustment
3.
Playback level adjustment
Deck B
1.
Dolby NR
level adjustment
2.
Head azimuth adjustment
3.
Playback equalizer adjustment
4.
Playback level adjustment
5.
Level meter display check
6.
Recording/Playback frequency response
7.
Recording level adjustment
O@B: HSHz, 160nwb/m
Fig. 10-1
Main unit
TP1 (L)
Fig. 10-2
VR404 (R)
{e)
Adjustment locations
VR701
am
obs y—@
@—vpAi01 (L)
VR202 (RI-@®
VR302 (L)-@
|
Dolby NR adjust-
Test tape STD-331B
e
Deck A
Playback equalizer
adjustment
VR101
(L)
VR2071 (R)
Playback level ad-
justment
VR102 (L)
VR202 (R)
Deck B
I
@- VR201 (R)
@—vr301 (Ll)
e
io
vr402 (RK
G-vAa01 (R)
@- VR303 (L)
ment
VR701
Playback equalizer
adjustment
VR301 (L)
VR401
(R)
Playback level ad-
justment
VR302 (L}
VR402 (R)
Recording/playback
frequency response
adjustment
VR304 (L)
VR404 (R)
Recording level
adjustment
VR303 (L)
VR403 (R)
@- vr403 (R)
e DECK
A ADJUSTMENT
1. Head Azimuth Adjustment
(with auto tape selector function)
@ Set VR102 and VR202 (playback level adjustment) to MAX positions (turn fully clockwise)
Tape selector
Mode
Input signal/test tape
Adjustment location
Measuring location
Adjustment value
Remarks
Apply
Play 10kHz —20dB
F
4
:
¢
"screw-
.
if
Head azimuth adjus-
Left and right play-
Maximum playback
"
NORM
PLAY
portion of STD-3318
ment screw.
back terminals.
signal level.
lock
ater
test tape.
(Fig.
10-3)
completing
9.
adjustment.
2. Playback Equalizer Adjustment
e Set VR1012 and VR202 (playback level adjustment) to the physical center positions.
Tape selector
Adjustment location
|
Measuring location
Adjustment value
Remarks
Mode
Input signal/test tape
Play the 315Hz
The playback levi at 6.3kHz
PLAY
—20dB and 6.3kHz
must be within —0.5 +0.5dB
—20dB portions of
of the level at 315Hz (see
the STD-331B
test
playback frequency response
tape.
in Fig. 10-4.)
3. Piayback Level Adjustment
e Adjust precisely since this adjustment sets the playback Dolby level.
NORM
VR101 (L)
VR201 (R)
Left and right play-
back terminals.
Mode
Input signal/test tape
Adjustment location
Measuring location
Adjustment value
Remarks
Piay the 315Hz 0dB
F
VR102 (L)
TP1 (L)
—5.2dBv
HOnM
PLAY | portion of the STD-
VR202 (R)
TP2 (R)
(550mV)
331B test tape.
e DECK
B ADJUSTMENT
(with auto tape selector function)
1. Dolby NR Level Adjustment
Tape selector
Mode
input signal/test tape
ail Adjustment location
Measuring location
Adjustment value
Remarks
Apply a 2kHz —10dBv
,
;
TP1 (L)
—2.2dBv
NOR
ORM
REC
(316mV) signal to the | 1
|Recording level control
TP2 (R)
(775mV)
recording terminals.
2
|DOLBY
NR switch......ON
Apply a 2kHz
-17.9dBv +0.2dB
—30dBv (31.6mV)
ye)
NORM
REC
om
3
VR701
TP2 (R)
signal to the re-
cording terminals.
e@ Set VR302 and
VR402 (playback level adjustment) to MAX positions (turn fully clockwise)
2. Head Azimuth Adjustment
Tape selector
Input signal/test tape
Adjustment location
Measuring location
Adjustment value
Remarks
Apply
""screw-
Play 10kHz —20dB
;
:
Left and right slag
:
ape
.
'
Head azimuth adjust-
%
Maximum play- — jlock'
GoM
PLAY
etal pied eg
ment screw.
back eee
back signal level.
jafter com-
a
(Fig. 10-3)
pleting
ees Ae
abe
_jadjustment.
3. Playback Equalizer Adjustment
@ Set VR302 and VR402 (playback level adjustment) to the physical center positions.
Tape selector
Mode
Input signal/test tape
Adjustment location |
Measuring location
Adjustment value
Remarks
Play the 315Hz
The playback level at 6.3kHz
—20dB and 6.3kHz
VR301
(L)
Left and right
must be within —0.5 +0.5dB of
NORM
PLAY
—20dB portions of
VR401
(R)
playback terminal
the level at 315Hz (see play-
L-R
back frequency response in
Fig. 10-4.)
the STD-331B
test
tape.
4. Playback Level Adjustment
Tape selector
Mode
Input signal/test tape
Adjustment location
pean |
Play the 315Hz 0dB
PLAY
portion of the STD-
wales ey
5 Level Meter Display Check
331B test tape.
Tape selector
Mode
Input signal/test tape
Adjustment location
Apply a 315Hz
NORM
REC
~10dBv (316mV)
f
signal to the recording
terminals.
6 Recording/Playback Frequency Response Adjustment
|
ees (e
e Adjust precisely since this adjustment sets the playback Dolby level.
Measuring location
Adjustment value
| Remarks
TP1 {L)
—5.2dBv
TP2 (R)
(550mV)
Level meter display
TP1 {L)
ee
TP2 (R)
NORM
OdB
Recording level control
—5.2dBv +0.5dB
Tape selector
Mode
Input signal/test tape
Adjustment location
Measuring location | Adjustment value
Remarks
Apply a 315Hz
=
TP1(L
=
NORM
REC
"30dBv (31.6mV) ;
1
{Recording level control
ea
25.2dBv
signal to the recording
TP2 (R)
(55mvV)
terminals.
Record 315Hz and
Repeat the recording and play-
6.3kHz signals on the
back processes and adjust ac-
:
VR304 (L)
TP1 (L)
;
:
NORM
REC/PLAY|
STD-6O08A test tape,
2
VR404 (R)
TP2 (R)
cordingly until the 6.3kHz
and then play back
playback tevel is within +1.0
signals.
+0.5dB of the 315Hz level.
©
Change the test tape and the DOLBY NR
switch position and check that the frequency response zone indicated in Fig. 10-5 is satisfied.
415
38
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