EasyManua.ls Logo

Fostex A-8 - Page 79

Fostex A-8
100 pages
Save Page as PDF
Print Icon
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
The
test
point
for
TRACK
2
is
TP-203
located
near
relay
L-201.
The
GND
pin
to
be
used
is
located
left
of
the
REP
CAL
pot,
R324;
erase
current
is
adjusted
by
the
core
of
L-203.
6.4.6
Bias
current
adjustment
The
track
of
which
bias
current
is
to
be
adjusted
is
put
in
the
record
mode.
To
adjust
TRACK
1,
for
example,
hook
the
oscilloscope
probe
hot
side
to
TP-102
located
near
connector
J-101,
and
the
ground
clip
to
the
GND
pin.
Then,
set
the
BIAS
LVL
pot,
R317,
47KflB
at
approximately
450mV
P-P.
For
an
accurate
adjustment,
load
a
blank
tape
(Ampex
#457,
Scotch
#227)
on
the
recorder,
record
a
test
signal,
set
the
NR
switch
to
INT,
and
trim
the
BIAS
LVL
pot
so
that
the
overall
frequency
response
is
within
3dB
between
250Hz
and
lOKHz,
or
within
5dB
when
the
higher
end
is
14KHz.
During
this
adjustment,
temporarily
set
the
screwdriver
adjusting
slot
of
REC
EQ,
R316,
IKfiB
so
that
this
slot
is
parallel
with
the
PCB
plane,
then
trim
it
for
a
more
flat
overall
frequency
response.
6.4.7
Recording
level
adjustment
1)
Proceed
to
the
following
adjustments
only
after
checks
and
adjustments
in
the
previous
Sections
6.4.1
*v
6.4.6
have
been
completed.
Set
the
front
panel
NR
INT/EXT
switch
to
EXT.
2)
Load
a
blank
tape
(Ampex
457
or
Scotch
227)
on
the
transport
and
apply
an
audio
oscillator
output
of
400Hz,
-lOdBV
(0.3V)
to
the
INPUT
jack
on
the
recorder
rear
panel.
Also,
plug
in
a
level
meter
to
the
OUTPUT
jack.
Taking
TRACK
1
as
an
example,
the
connector
number
is
H
l"
for
both
INPUT
and
OUTPUT
jacks.
3)
Depress
the
RECORD
TRACK
1
button,
then,
depress
the
RECORD
and
PLAY
buttons
to
put
TRACK
1
in
the
record
mode.
When
thus
in
the
record
mode,
the
meter
will
indicate
the
input
level
regardless
to
select
position
of
the
input
button.
Check
to
see
that
the
reading
of
this
meter
is
0
VU
±1
VU.
4)
It
will
be
convenient
to
rewind
the
tape
to
the
start
if
the
tape
index
counter
reset
button
is
depressed,
at
start
of
recording,
to
return
the
display
to
0000.
5)
After
recording
a
certain
length
of
400Hz,
0
VU
signal,
depress
the
ZERO
RTN
83

Table of Contents

Related product manuals