4. PREVENTIVE MAINTENANCE

No preventive maintenance is necessary for any type of FDDs under normal conditions of use.
However if it is determined that adjustments are necessary, the following must be done.

• Adjustments (Refer to table 4.1)
(1) Specify an applicable model from Table 4.1, and make a read/write head radial adjustment at a specified track.
(Sides 0,1)
(2) Make an index timing adjustment at a specified track. (Sides 0,1).
(3) Make an azimuth measurement at a specified track (Sides 0,1)

CAUTION
Do not write when using alignment diskette. Check that write protect sensor is properly operating with a data diskette.
Note: Section 9 describes the adjustment procedures in detail.

5. ADJUSTMENTS AND VERIFICATIONS

5.1 Motor Speed Verification (Index Period)

(1) Insert a diskette, run the motor, and clamp. Refer to the index period column of Table 4.1 for the applicable model.
(2) Step to the specified track.
(3) Connect a frequency counter to the INDEX signal.
IX (INDEX)
(4) Check that the frequency counter readings meet the specifications in the table.

5.2 Write Protect Verification

(1) Check that the exerciser's write protect lamp goes on and off as a media is inserted and removed as specified in the table below.

Media with write protect hole open: ON
Media with write protect hole closed: OFF

5.3 Head Output Verification

Use a new diskette if possible to identify head failure for this check.
(1) Insert a good diskette.
(2) Run the motor.
(3) Step to the track specified in the output level column of Table 4.1.
(4) Connect the oscilloscope probe as specified below.

CH1 : T1
CH2 : T2
EXT : IX (Index)

Invert channel 2 and select the Add mode.
Set vertical deflection to 10mV/division and horizontal deflection to 20ms/division.
(5) Write 2F (all ones) on the entire circumference.
(6) Check that the average output level meets the specifications of Table 4.1. If it does not meet the spec-ifications, refer to item
7 of the Trouble Analysis Table.

5.4 Output Modulation Verification

Modulation: M is calculated by the following formula.

M(%) = Vmax - Vmin x 100 using the value obtained in 5.3, and check that the calculated value is 20% or less.
M(%) = Vmax + Vmin


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