Sanyo MR-1020 - Sanyo MR-1020 Various Pressure Adjustments; Pinch Roller Pressure Adjustment; FWD Roller Pressure Adjustment; Left and Right Idler Adjustment

DUI. Various Pressures
1. Pinch roller pressure
*
Tie
a
string
onto
the
pinch
roller
shaft
as
shown
in
figure
7.
*
Turn
on
the
power
and
pull
the
string
with
a
spring
scale.
Read
the
number
when
the
roller
stops
turning.
*
Suitable
pressure
is
from
1
to
1.5k
gr.
|) Capstan
Pressure ©
Roller
2. FWD roller pressure
Measure
both
left
and
right
FWD
rollers.
The
figure
8
shows
only
the
left
FWD
roller
because
they
are
both
the
same.
Move
the
roller
lever
in
the
direction
of
the
arrow
by
pushing
with
a
spring
scale
on
one
edge.
Read
the
pressure
when
the
roller
separates
from
the
left
reel
base.
* Normal pressure is 600 - 1000 gr.
*
Adjustment
is
done
with
the
coil
spring
(J26)
and
link
(324
or
J25).
Fig. 7
Spring (126) Spring (J26)
Lever (J21)
Fig. 8
3. Left and right idler adjustment
*
Pull
the
PLAY
pressure
idler
as
shown
in
figure
9.
Examine
the
left
idler
pressure
when
the
unit
is
set
for
ordinary
winding
to
the
right;
examine
the
right
idler
pressure
when
it
is
set
to
Motor Pulley
Fry wheel
Fig. 9
O
run to the left.
*
Proper
pressure
for
both
idlers
is
250-+
30
gr.
*
If
the
pressure
is
not
within
this
range,
change“the
idler
pres-
sure
spring
(J11).
ELECTRICAL
ADJUSTMENTS
I. Bias Oscillator Frequency
OSCILLOSCOPE
AF oscillator
Fig. 10
As
shown
in
figure
above,
connect
a
10
ohm
resistor
in
series
with
the ground lead wire of the Record/Playback head.
Connect
the
vertical
input
of
the
oscilloscope
across
this
resistor;
connect
the
horizontal
input
of
the
oscilloscope
to
the
output
terminal
of
the
Audio
Frequency
Oscillator
(A.F.
Oscillator).
With
this
unit
set
to
RECORD
mode
and
connected
as
above,
a
lissajous figure will appear on the oscilloscope.
Standard frequency is 80K Hz +5k Hz.
It
is
only
necessary
to
measure
one
channel.
If
the
frequency
is
not
within
the
above
range,
change
OSC
coil
or
C102
(0.003
mfd.).
Bias current 1.0 mA.
Proper
bias
is
necessary
for
optimum
recording.
Adjust
the
bias
oscillator
frequency
as
described
above.
Bias
current
during
the
recording
is
measured
at
both
ends
of
the
connected
resistors.
Adjustment
is
made
by
the
semifixed
CT-1,
CT-2,
so
the
voltage
will be 10 mV onan AC VIVM.
Recording
bias
current
is
1.0
mA
(voltage
across
the
10
ohm
re-
sistor: 1.0mA x 10-8 x 10=0.01 V).
II. Gain Balance Adjustment
1. Connect an audio signal generator to the MIC jack of channel 2
and feed lk Hz 0.4 mV signal. Use an attenuator as shown below.
AUDIO
SIGNAL
VTVM
GENERATOR
ATTENUATOR
600
ohm
Rocord mode
. Operate the unit in Record position.
. Connect the VITVM across R93.
. Read the VITVM indication.
.
Reconnect
an
audio
signal
generator
to
the
MIC
jack
of
channel
1
and
feed
Ik
Hz
0.4
mV
signal.
. Reconnect the VITVM across R43.
7,
Adjust
SVR-1
for
the
same
VTVM
readings
on
charanels
1
and
2.
UW & Why
n