Output Modulation Verification; Resolution Verification; Radial Alignment Verification And Adjustment - Panasonic JU-475-4 Service Manual

9.4 Output Modulation Verification
9.5
9.6
Modulation is calculated by the following formula.
max 7 Vmin
Modulation = Amae Vin x 100 (%)
Vmax + Vmin
Using the value obtained in section 9.3, and check that the calculated value meets the
specifications of Table 8.1.
Maximum voltage Value: Vmax
Average Voltage
Minimum Voltage Value: Vmax
Fig.9-1 Modulation
Resolution Verification
(1) Leavethe oscilloscope in the same condition as mentioned in section 9.3.
(2) Resolution is calculated by the following formula.
Resolution = V2raverage x 100 (%)
Vif average
(3) Check that the calculated value meets the specifications of Table 8-1.
Radial Alignment Verification and Adjustment
Introduction
This adjustment is normally not necessary.
If the mounting screws for the stepper motor loosen, or if parts become defective, or if a
compatibility error occurs, check and readjust according to the following procedure.
Steps(4) to (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 3-1.
(1) Insert Panasonic 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 8-1.
(3) Leavethe oscilloscope in the same condition as mentioned in section 9.3.
e CatsEye System
(4) Check the output waveforms for sides 0 and 1. They should appear as in Fig. 9-2.
(5) The two waveforms should appear in the amplitude ratio in the radial alignment column of
Table 8-1 or better.
(6) I the specified ratio is not satisfied, loosen the two mounting screws for the stepper motor.