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Fujitsu M255XK Customer Engineering Manual page 45

5 1/4" mini-flexible disk drive
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4.4.5 Disk Rotational Speed
Tools Required:
Disk Drive Power Supply
Exerciser (AVA 409 or equivalent)
Oscilloscope
Soft Sector Work/Scratch Diskette
Proceed as follows:
1.
Connect the frequency counter to the INDEX interface signal (pin-B).
2.
Start the Spindle Motor and load the work/scratch diskette.
3.
Seek the Read/Write heads to Track 00.
4.
Make sure the timing interval of the INDEX interface signal is 200 ±3 milli-
seconds at 300 RPM and 166.7 ± 2.5 milliseconds at 360 RPM.
4.4.6 l-lead Contact Inspection and Adjustment
Tools Required:
Work/Scratch Diskette
Flat Blade Screwdriver, small
Exerciser (AVA 409 or equivalent)
Oscilloscope
Screw Lock Liquid
Proceed as follows:
1.
Connect the oscilloscope to TP1, TP2 (Pre-amp T est Points) on the main
circuit card. Set the oscilloscope range to AC rhode, 0.2V.
2.
Load the work/scratch diskette and start the Spindle Motor.
3.
Seek the Read/Write heads to the innermost track.
4.
Record and then read a constant "2F" on the entire track (2F is a l's only
WRITE DATA frequency of 250kHz for M2552K and 500kHZ for M2553/54K).
5.
Write down the average values shown on the oscilloscope while performing
step 4.
6.
Refer to Figure 4-7. Insert a thin rod into the inspection hole "1" of the Main
Circuit Card and press the top of the head very slightly to apply about 4 to 7
ounces (10 to 20 grams). Repeat steps 4 and 5 with the weight applied.
7.
Compare the average values found in steps 5 and 6.
Ensure the Read Level
measured in step 5 is BO% or more of the value measured in step 6.
B.
Repeat steps 4 through 7 for side 0 and side 1.
9.
Seek the Read/Write heads to Track 00 and repeat steps 4 through B.
TS-021-0130B7 ••• 01
4-13

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