Teac FD-55 Series, Maintenance Manual

Page: 132 / 216

(b) Start the spindle motor and install an alignment disk.
(c) Execute head loading.
(d) Set the head to the following alignment check track.
48tpi: track 16
96tpi: track 32
(e) Confirm that two lobe patterns as in Fig.430 can be observed (it is
not necessary that the levels of VA and VB are equal).
If only one lobe pattern can be observed or if two lobes become one
pattern, the head is not on the alignment check track.
In such event, execute step-out or step-in as mentioned below to
obtain the most similar waveform to that in Fig.430.
48tpi: 2 tracks
9&tpi: 4 tracks
Note: The above number of tracks to be stepped is required.to make the
alignment track position be fit with the magnetized condition of
the basic magnetized phase "A" of the stepping motor. If the
stepped track, numbers are inassured, set it again from track 00
(TRACK 00 output: signal becomes TRUE) .
Foir a 48tpi FDD, the lobe pattern as in Fig.430 should be observed
at the track of even number. For a 96tpi FDD, the lobe pattern
should be observed at the track of multiple number of four (4).
(f1 After one or several step-outs from the check track, step in the
head to the check track again and measure VA and VB at that time.
(g) Calculate the true value of misalignment by substituting the value
in item (f) and ALIGNMENT calibration value (see alignment disk label,
attention to the side).
4094