Spindle Speed Adjustment; Radial Track Adjustment - AMSTRAD PC1512 Service Manual

5.
Adjustments and
Checks
5-1 Spindle
Speed Adjustment
a)
Insert
and clamp
a blank diskette by rotating
the motor.
b)
Stop on
track.
c)
Connect
the frequency counter
to
TP6.
d)
Rotate the speed
adjusting variable resistor
on
the spindle-motor printed
circuit
board
and
adjust so
that
the counter
shows 200
+2
ms.
If
the spindle-motor
is
not
an
adjusting variable resistor type,
check
the counter
shows
200 ±2 ms
only
and
adjusting
is
unnecessary.
fc
^_
5-2 Radial Track Adjustment
a)
Insert a
CE
diskette.
b)
Move
the
head
to
Track
1
6
and check
the cat's-eye
waveforms
of
the top
and bottom
heads.
c)
Adjust as follows
if
one
of
the top
or
bottom heads
is
not
more
than
75%
in
an amplitude
ratio of
two waveforms.
d)
Slightly
loosen the
fix
screws
of
the stepping
motor assembly and
move
the stepping
motor
assembly back and
forth to
adjust the amplitudes.
The
amplitudes
of
two waveforms should be
nearly the
same.
Then
tighten the rear screw.
e)
Check
the cat's-eye
waveforms
of
the top
and bottom heads.
f)
Repeat
from
d)
if
adjustment
fails.
Measuring
Conditions
Channel
1-TP1 (10mV/div)
MODE-ADD
Channel 2-TP2
(10mV/div)
Sweep-20ms/div
Head Reading Outouc Signal
(TP1 -TP2)
—
X
I
2;
7
5
%
b
Fig. 5-
11