Adjust the height of
the
bias head
by the
height
adjustment screw
(ref.
fig.
1) until max. reading is
obtained
on
both
V.T.V.M.
Check
that
the
tape
runs
freely in the
groove
in front
of
the
bias head and
that
there
is
sufficient
clearance between the bias
head and
the
mounting
plate
for
the record head.
The height
position
of
the
bias head is not
critical,
and
if
the clearance between
the bias head and the
mounting
plate
for the record
head is
insufficient,
raise
the bias head slightly.
3.3.2
Horizontal
alignment:
Connect two V.T.V.M.
to both
CATHODE
FOLLOWER
outputs, and
connect a signal
generator
to the Hl-
LEVEL inputs
CHI and CH2.
Set
the
tape recorder
to
stereo recording al 71lz i.p.s.
and
turn
both
play-
back volume controls
to max.
Record
a 1000
c/s
signal.
Untighten the
fixing
screw
for
horizontal adjustment
(ref.
fig.
'1)
and
move the
bias head from the
extreme
Ieft
position
towards
the recording head
until
max.
reading
is
obtained
on both
V.T.V.M. The output level
should now
be approx..5V,
readjust
the record
gain
controls until this is
obtained and check
the
horizon-
tal
position
of
the
bias head. After
one has assured
that the
horizontal
position
is
correctly
adjusted,
tighten the
adjustment
screw making
sure that
the head is
not being moved.
This is eventually
indicated
by
a
loss
of the output level.
A fine-adjustment
of
the
bias current is
obtained by
the
pot.meters
R609
(CH1)
and
R612
(CH2).
Adjust
R
609 and R
612 until max. reading
on
the optput
meters
are obtained.
3.4 The
erase head.
3.4.1
Height adjustment:
The erase head is
set
in
a
preliminary position
where
approx.
0.25 mm
(.01")
of
the
ferrite core for the
upper track
of
the
erase head is visible
above the
tape. Insert
the test tape No.
9 and
record
a 1000
c/s
signal from the
generator
on
ch. 2 at maximum re-
cording level. Dip
the
tape in
the Magna-See
solution
and
check that the re-recorded
track lies
in
center
of
the
erased track. Make
sure that the
erase head
does
not
erase any
part
of
the adjacent tracks.
3.4.2 Azimuth
alignment:
Align the
azimuth
position
of the
erase head by the
azimuth adjustment
screw. The
erase head
should
be
parallel
with the
mounting
plate
for the
heads
(15.4).
The
azimuth
position
of the erase head is not
critical.
3.4.3 Lateral
alignmenl:
Turn the
head mounting
plate
for the
erase head, until
the front
of
the
head is
parallel
to the
pressure pad.
3.5 Model
62x.
10
000- 5000
-
1C00
-
100-
50-250 c/s
recorded
at71/t
i.p.s. tape
speed. The tape
conforms
with the N.A.B.
standards. The
output tolerance is
-+
2
dB
for
all
frequencies.
The
difference in
level
between the
two
channels
should be less than
3
dB.
4.2
Adjustment
of the
playback
amplifiers:
Play
back
the test
tape No. 4 with
the output
volume
controls
to maximum. This is
a full track
prerecorded
tape
with 400 c/s
at71/z i.p.s. tape speed.
Ad.just the
potentiometers
R233
(CH
1)
and
R234
(CH
2)
until
the
reading
on the
output meters
are 1.3V.
5.0 Adjustment of
the record
current
(A-B
test) and
the
electronic
beam indicators.
Make
sure
that
all adjustments
under
paras
1.0,
2.0
and 3.0 are made before
proceeding
with these ad-
justments.
Connect a
signai
generator
to
both Hl-LEVEL
inputs
and two V.T.V.M.
to both
CATHODE
FOLLOWER
out-
puts.
Record
a 4O0
cls signal in
stereo A-test, with both
playback
volume
controls to max. at 7tlz i.p.s. Adjust
the record levels
by the record
gain
controls
until
the output
levels
are
1.5 V. Depress
the
push-buttons
lV and V
(stereo
B-test) and
adjust
the
record current
by
R115
(CHl)
and
R116
(CH2)
until the readings
on
the output meters
are 1.5 V.
Adjust
R 137
(CHl)
and
R
138
(CH2)
until the elec-
tronic
beam indicators
are
closing.
Release the
push-
buttons lV
and V
(stereo
A-test)
and
check
that the
readings
still are 1.5 V on
the output
meters.
6.0 Head alignment
without Tandberg
Test Tapes.
6.1 The
playback
head.
6.1.1 Height
alignnnent:
The
height
of the
playback
head is
aligned by the
height adjustment
screws. The upper edge
of
the tape
shall
run flush with
the
upper
part
of the airgap
for
channel
1.
6.1.2 Azimuth
alignmenl:
Play
back a standard
azimuth
alignment tape with a
V.T.V.M.
connected to
each cathode follower
output.
Adjust the
position
of
the
playback
head by the
azimuth
adjustment
screw,
until
maximum
reading is
obtained on the output
meters.
6.1.3 Lateral
alignment:
Pull
the
pressure
pad
(59.5)
away from the
erase head
when
the
standard azimuth alignment
tape is
being
played
back. The
output
level
should not
decrease
more
than 3 dB. Adjust
the
lateral
position
of
the
playback
head, if
necessary,
by turning
the head
mounting
plate.
All
the
alignments
specified
in chapters
3.1, 3.2, 3.3,
6.2
The
record
bead.
and
3'4 are valid for
model 62x with
the exception-o1
iorro*'in"l
instructions
given
under
para3.z.
paragraph
3.1.2 which
is
superseeded by 6.1.1
and
paragraph
3.2.3 is
superseeded by 6.6.2.
6.3
The
bias head.
4.0
control
and adiustment
ol
playback
amplifiers,
Follow
the instructions
given
under
para
3'3'
with
Tandberg
test tapes.
6.4 The erase
head.
4.1
Control of
the
playback
amplifier:
6.4.1 Height
alignment:
Play
back the test
tape No.
3.
This
is
a full track
pre-
The
height
of the erase
head is
aligned by
the height
recorded
tape with the
following frequencies:250-
adjustment
screws. Approx.0.25
mm
(.01
")
of the
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