IBM 3270 Maintenance Manual page 217

Use the Drive Motor Preliminary Speed
Adjustment to ensure the diskette drive speed is
correct (see Section 5, "Removal/Replacement
and Adjustments").
Note: Fluorescent lighting is needed to see the
strobe effect on this test.
Type 1
Type 2
IS THE SPEED OF THE DISKETTE DRIVE .
CORRECT?
NO Adjust the speed of the diskette drive. If·
you are unable to adjust the speed, replace
the diskette drive (see Section 5,
"Removal/Replacement and Adjustments").
YES
8-600-18 Maintenance Information