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Playback Level Setting (Refer to Fig. 10)
12.
Disconnect
A-4000
output cables from
(output)
jack, and change
the connection
of VIVM
from the RA-40
output
jack to A-4000
output
'jack (Fig. 10-a).
13.
Play (7-1/2 ips, forward) 700 cycle tone recorded at normal operat-
ing level
by using a standard
alignment
tape.
14.
Adjust
the playback
level
control
on the printed
circuit
board
(VR-1 for Channel
A, VR-2
for Channel
B) to obtain
+4 BD reading
on
the VIVM.
15.
Stop
the tape and change
the VIVM from
the A-4000
output
jack to
RA-40
output
jack.
Connect
A-4000
(output)
jack to RA-40
(to deck
output) jack (See Fig. 10-B).
16.
Rewind
the tape to normal
operation
level
and playback.
Adjust,
the
playback
level control
to obtain
O VU reading
on the VU meter.
NOTE:
When the VU meter
indicates
0 VU and the OUTPUT level
controls
at maximum position,
the output level is approx.
+4 db (1.2V).
Playback Noise Check
1.
Play 700 cycle tone
(normal operating level),
and adjust
OUTPUT?
level controls so that VIVM reads exactly 0 db (0.775V).
2.
Stop the
tape and read
noise
level
on the VIVM.
NOTE:
The signal to noise
ratio
measured
from 3% distortion
level (peak recording level) is generally obtained by
adding 6 db to the value measured
above.
Playback
Amplifier
Check
For playback
amplifier
check,
connect
a signal
generator
to playbakk
input
circuit
as shown
in Fig.
12.
Check
the
frequency
response,
noise,
amplifier
gain,
etc.
NOTE:
1.
Excessive
input may cause
overloading
and distortion
in
-
24 -
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