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Fujitsu M255XK Customer Engineering Manual page 50

5 1/4" mini-flexible disk drive
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4.4.10 Track Alignment
Tools Requi red:
Phillips Screwdriver, M3
Alignment Disk
Flat Blade Screwdriver, medium
Exerciser (AVA 409 or equivalent)
Oscilloscope
Intraconnector 34-pin
Relative Humidity Meter
Screw Lock Liquid
Note:
Perform track alignment inspection and adjustment at normal room
temperature and
humidity.
Avoid
extremely
low
temperatures
or
extremely low or high humidities (even if the Disk Drive is normally used
under these conditions).
Place the Disk drive and disk in a normal
environment for 2 hours before starting the following procedure.
When inspecting the alignment, place the Disk Drive in the position in
which it is normally used (horizontal or vertical).
Proceed as follows:
1.
Connect the oscilloscope channels to TP4 and TP5.
Set the oscilloscope to
AC mode, with both channels to 0.5 volts per division,
Set the time base at
20 milliseconds per division. Put one of the channels in invert mode, and put
both channels to ADD.
Connect the trigger input to pin-B of the intra-
connector (between the drive and exerciser).
2.
Start the Spindle Motor and load the alignment diskette.
3.
Seek the Read/Write heads to Track 32, from track 0 (outermost track).
4.
Check for a pattern of two lobes (VA and VB levels need not coincide).
Figure 4-11 Lobe Pattern for Track Alignment
a. If only one lobe pattern is observed, or when the two lobe patterns are
connected, the head is off-track.
In this case proceed to the alignment
procedure given in step 5 below.
b.
If
lobes VA and VB are within 20% of each other then seek the heads
inward 4 tracks (track
36)
then outward 4 tracks (track 32).
Note:
The percentage of lobe VA to VB is measured by adjusting the variable
gain on channels
A
and B until the larger lobe is
5
divisions in amplitude.
The lobes are then compared and should be within 1 division of each other
(each full division is equal to 20%, and each of the minor divisions are
equal to 4%).
TS-021-0130B7 ••• 01
4-1B

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