1.0 Alignment
It
is important that
the
contact
between
the
tape and
the
heads
on
the tape
recorder is
good.
To
obtain
this
contact the
tape should be run through the
tape
recorder
5-10 times at normal speed
to have the
tape
polished
before measuring
the
frequency
re-
sponse and
the signal
to noise
ratio.
1.0.1 Demagnetizing
Demagnetize
the heads and adjacent
parts
before
aligning
the heads.
1.0.2. The mounling
plate
lor the heads
The
height of the mounting
plate
for the
heads
(15.4)
is
aligned by the adjustment screw
at the
rear
of
the
playback
head. Move
the operating lever
slowly
to
normal forward
drive
with
a
tight
tape
inserted.
Align
the
height of
the
mounting
plate
for the heads
until
the
tape
runs
equidistant
from the
flanges of the tape
guide
(79,2).
1.0.3
The adjustable tape
guide
Set the
operating lever in
normal forward
drive
with
tape
inserted
and depress the
push-button
lll. Align
the
adjustable tape
guide
(79.3)
until
the
tape
runs
equidistant
from the
flanges
of
the adjustable tape
guide.
Repeat
1.0.2.
2.O Adjustment of
the
oscillator and bias head
circuits.
2.0.1 Insert
one
10 ohm resistor
in series with each
bias head half to
ground
and
connect
a V.T.V.M.
across each
resistor.
2.O.2
R 609 and
R
612 is turned up
to
1 o'clock
posi-
tion while R607 and R610 are
set
to approx. 11
o'clock. Rel. fig.
3.
2.0.3 Set
the
tape
recorder
to stereo recording and
the
speed selector
to
7tlu i.p.s.
2.0.4 Use a
calibrated
long wave
receiver, frequency
meter or
frequency
counter for the indication
and
adjust the oscillator
frequency
by
C 610 until f/osc.
=
85.5
kc/s.
2.0.5 Set the
tape recorder
for mono recording
CH
1
and
the
speed selector to 7tlz
i.p,s.
2.0.6
Adjust
the oscillator
frequency with
L601
F/osc.
will
then
be
85.5 kc/s.
2.0.7
Set
the
tape
recorder for mono recording CH 2.
2.0.8 Readjust L
601
to
compromise
if necessary. The
osc.
frequency
deviation between mono recording
CH 1, CH
2
and stereo
should
be less
than
2
kc/s.
The deviation should be indicated
with
frequency
meter, long wave
receiver or
frequency
counter.
2.0.9
Adjust
C 602
and
604
to max. reading on the
V.T.V.M.
(between
100 mV and 400 mV).
3.0
Head
alignment
and track
control
with
Tandberg
Test Tapes,
Model
64x
3.1.
The
playback
head
3.1.1 Connect
one
V.T.V.M.
to each
CATHODE
FOLLOWER
output.
3.1.2 Height
alignment:
Play back
the test tape
No. 1.
This is
a full track
pre-recorded
tape with
1000
c/s recorded
atTt/zi.p.s.
tape speed.
The record level of the
exact
area
corresponding
to track 3 is
reduced
30 dB.
Adjust
the height of the
playback
head
until
minimum output
is
botained on a
V.T.V.M. from
track
3
(ch.
2).
3.1.3
Azimuth alignment:
Play back the test tape No.
2. This is
a
full track
pre-recorded
tape with 10.000
cls al 71lz i.p.s. tape
speed.
Adjust the
azimuth
position
of
the
playback
head until maximum reading
is obtained on both
output
meters.
3.1.4.
Lateral
alignment:
Check
the
lateral
position
of
the
playback
head by
pulling
the
pressure pad
(59.5)
away
from
the erase
head when
the test
tape
No.
2 is
played
back.
The
output level
should not decrease more
than 3 dB.
Adjust the
lateral
position
of
the
playback
head, is
necessary,
by turning the head mounting
plate.
Re-
adjust the
azimuth
position.
3.2
The
record
head.
3.2.1
Adjust
the horizontal
position
of the bias
head
until
the
head is in
center of the record head. Ref.
fig. 1.
3.2.2
Adjust
the height
of
the
bias head until
the
tape
runs freely
in the
groove
in front
of the
bias
head.
3.2.3
Height
alignment:
The
record
head is
set
in a
preliminary position
where
approx.
0.1 mm
(.0025")
of
the
lamination for the
upper track is visible
above the tape. The
position
of
the record
head can
be
inspected
by using the iron
powder
method
(Magna-See).
Record all
four tracks
on the
tape
and dip the tape in the solution. The
pattern
on the tape will
show il the
position
of the
head is
correct.
Readjust
if necessary.
3.2.4
Azimuth
alignment:
Connect
a signal
generator
to the HI-LEVEL inputs
CH1 and
CH2,
and
two
V.T.V.M.
to
the
CATHODE
FOLLOWER
outputs
CH1
and
CH2.
Make a
stereo
recording in
B-test al 7t/z i.p.s. of
a
15.000 c/s
signal.
Adjust
the azimuth of the record
head to
max. reading
on
the
output
meters.
The out-
put
level
should now be approx. 100 mV with the
playback
volume controls
to max.,
readjust
the record
gain
controls until this is obtained and
check
the
azimuth
position
of the record head.
3.2.5
Lateral
alignment:
Check the
lateral
position
of the
record head
by
pulling
the
pressure pad
(59.5)
away
from
the erase
head during the recording.
The output level should
not
decrease
more
than 3
dB.
Adjust the
lateral
position
of the record head, if necessary, by turning
the head mounting
plate.
Recheck the height and
azimuth
position
of
the head. Ref.
para.
3.2.3 and
3.2.4.
3.3
The
bias
head.
3.3.1
Heighl
alignment:
Connect
two
V.T.V.M.
directly across the
recording
heads.
Set
the tape recorder to
stereo
recording at
71 lz
i.p.s.
and turn both
playback
volume controls
down
to
0.
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