Teac A-3300SR - Bias Trap Adjustment; Record Head Azimuth Adjustment; Bias Adjustment

8-14 BIAS TRAP ADJUSTMENT
OUTPUT SW ............ TAPE
REC MODE SW ............ ON
BIAS and EQSW ...:........ 1
Select REC PAUSE mode
iy . Remove all input signals.
2. Connect a VTVM or Oscilloscape from ground to the
junction of L-302 and C-312 (L-ch) and from ground to
the junction of L-304 and C-330 (R-ch). See Fig. 8-7.
3. Adjust L-302 (L-ch) and L-304 (R-ch) for minimum
reading on scope or VITVM.
Use Plastic alignment tool.
Test Points
ON REC METER AMPL.
T-669
Fig. 8-7 Bias Trap Test Point
8-15
RECORD
HEAD
AZIMUTH
ADJ.
Tape
SPEED
SW.........-.-
LOW
NOTE:
The
effect
of
turning
the
azimuth
screw
will
reg-
ister
on
the
VTVM.
A
slight
delay
will
be
noticed.
Therefore,
the
screw
must
be
rotated
slightly
with
a
pause
to
see
the
effect.
— FINE ADJUSTMENT —
4.
Connect
a
VTVM
to
the
OUTPUT
jack
and
an
AF
oscillator
to
the
LINE
IN
jack.
Set
the
oscillator
to
10
kHz
at
—18
dB
(97
mV).
.
Begin
recording
(Depress
REC
and
PLAY
buttons).
6.
While
recording
and
monitoring
the
tape
playback,
adjust
the
azimuth
screw
for
maximum
reading
on
the
VIVM.
NOTE:
It
is
absolutely
essential
to
accomplish
the
above
adjustment
before
performing
the
following
adj.
to
avoid
phase
errors
greater
than
45°.
7.
Sweep
the
signal
from
40
Hz
to
16
kHz
for
7-1/2
ips
speed
(or
40
Hz
to
10
kHz
for
3-3/4
ips
speed)
and
adjust
the
azimuth
so
all
signal
are
within
45°
between
channels.
8. Secure the screw with insulating locking paint.
ws
RECORD PERFORMANCE
OSCILLOSCOPE
OSCILLATOR
ATTENUATOR
(L} OUTPUT
under TEST [2
T-621
Fig. 8-8 Test Connection for Recording Check
8-16 BIAS ADJUSTMENT
Be
sure
the
Bias
Trap
have
been
adjusted
per
section
8-14
before
proceeding.
Tape SPEEDSW........... LOW
BIAS and EQSW ............ 1
9.
Apply
7
kHz
signal
at
—18
dB
(97
mV)
to
the
LINE
IN
jacks.
10.
While
recording
on
the
YTT-8013
Test
Tape,
adjust
ca-
pacitor
VC-401/VC-403
for
peak
reading
on
the
VTVM,
then
turn
the
capacitor
clockwise
until
a
decrease
of
4
dB
from
the
peak
is
obtained.
BIAS and EQSW ............ 2
11. Apply 400 Hz signal at —8 dB (308 mV) tothe LINE
IN jacks.
12. While recording on the YTT-8023 Test Tape, adjust ca-
pacitor VC-402/VC-404 for peak Bias.
Peak Bias
400 kz
Decrease 4458
OUTPUT LEVEL (dB) o
BIAS CURRENT (mA)
Fig. 8-9 Bias Limits Chart
ne