Teac A-3340 - A-3340 ELECTRICAL MEASUREMENT AND ADJUSTMENT; SPECIFIED OUTPUT LEVEL FOR A-3340; VU METER CALIBRATION (PLAYBACK) FOR A-3340

8.A-3340
MEASUREMENT
AND
ADJUSTMENT
-ELECTRICAL-=
Outlined
procedures
refer
only
to
FRONT
channels,
the
same
procedures
also
apply
to
REAR
channels.
Before
performing
checks
set
all
head
function
selector
switches
to
NORMAL
position.
Power supply check and adjustment.
Check
the
voltage
at
VR-1
and
adjust
to
24V
DC if
required.
(Refer
to
control
board
on
the
schematic
diagram.
)
Place
MONITOR
switches
(L1-R3,
L2-R4)
in
TAPE
position,
place
tape
speed
control
at
H
(high),
place
PLAY
switch
in
4
CHAN
position.
SPECIFIED
OUTPUT
LEVEL
————
_OvroOwnwm—m—mo
1.
Play
the
400
Hz
tone
in
section
1 of
the
test
tape.
This
tone
is
recorded
at
operating
reference
level
(1%
of
the
THD
level).
THD: Third Harmonic Distortion
2.
Turn
the
output
controls
fully
clockwise,
and
adjust
VR
201/203
for
+2
dB
reading
on
level
meter.
3.
Then
retard
output
controls
until
a
-8
dB
is
obtained
on
the
level
meter
at
the
OUTPUT
jacks.
NOTE
This is the specified output level. Do not
disturb
this
setting
until
the
remaining
ad-
justments have been completed.
VU METER CALIBRATION (PLAYBACK)
4.
While
playing
the
400
Hz
tone
(1%
THD)
in
section
1
of
the
test
tape,
adjust
VR
202/204
for
reading
of
0
VU
on
the
VU
meters.