5.5 Radial Alignment Adjustment

Introduction
This adjustment is normally not necessary.
If the mounting screws for the steeper motor loosen, or if parts become defective, or if a compatibility error occurs, check and readjust according to the following procedure.
Steps (4) and (9) below should be performed regardless of the type, CE or DAD alignment diskette used. Use an alignment diskette suitable to the type of FDD to be adjusted according to table.

(1) Insert an alignment diskette.

CAUTION:
Be sure to leave the alignment diskette under room conditions for 20 minutes before adjustment.

(2) Step to the track specified in the Radial alignment column of Table 4.1.
(3) Leave the oscilloscope in the same condition as mentioned in section 5.3.

• Cats Eye System

(4) Check the output waveforms for sides 0 and 1. They should appear as in Fig. 5.2.
(5) The two waveforms should appear in the amplitude ratio in the R/A +/- 42% or more.
(6) If the specified ratio is not satisfied, loosen the two mounting screws for She stepper motor.
(7) Move the stepper motor along the base by hand until the two waveforms assume approximately the same amplitude, and
retighten the mounting screws. (See Fig. 5.2).
(8) Step the head outward (track 0) and inward (track 40 or 79), and confirm that the adjustment has been completed.
(9) After the intitial adjustment, be sure to confirm track 00 sensor adjustment 5.8 and carriage limiter 5.9.

Fig. 5.2 Radial Alignment Waveforms (CATS EYE)

Note: Alignments on sides 0 and 1 are adjusted at the factory. If they are misaligned, adjust
them to meet the specifications of Table .

 

• DAD (Dynamic Alignment Diskette)

(4) Watch the output waveforms for sides 0 and 1. They should appear as shown in Fig. 5.3.
(5) Measure the timing levels A1 to A4 and B1 to B4 in Fig. 5.3., and calculate the lobe ratio from the following
formulas.

(6) The lobe ratio calculated by the above formulas should meet the specifications on item 3 of Table.
(7) If the above requirement is not met, loosen the two mounting screws for the stepper motor, adjust.
(8) Seek from track 0 to track 40 and from track 79 to track 40, and confirm that the adjustment has been completed.
(9) After the radial adjustment, be sure to confirm track 00 sensor adjustment 5.8 and head carriage limiter 5.9.

Note: An alignment instrument for 3.5 inch FDDs permits accurate and easy adjustment
because the lobe ratio is displayed on the instrument.

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