Stepper Drive Band Adjustment - IBM 6580 Product Support Manual

Stepper Drive Band Adjustment
CAUTION
When a diskette drive is removed from its mounting, the •
ground through the AC connector must be verified. Verify
the ground by checking for 0 ohms between the Diskette
Unit base and the diskette drive.
1. Turn the system power off.
2. Remove the read/write head cable connector and
guide.
3. Place the head carriage at track 40 (timing holes in
pulley and casting are aligned). Observe this condition
visually.
4. Loosen the three screws that attach the band to the
pulley and the carriage bracket . •
5. Tighten the right·hand carriage bracket screw. and
the band clamp screw. keeping the band parallel to
the edge of the pulley.
6. Block the head carriage approximately 25.40 mm
(1.0 inch) from the casting.
7. Use a paper clip and the push/pull scale to pull the
loose end of the band with 1135 grams ± 10% (2.5
pounds ± 10%) of force, and tighten the left·hand
carriage bracket screw. This adjustment ensures the
drive band tracks evenly and tightly over the stepper
pulley . •
8. Carriage must move freely from track 00 to track 76.
9. Load the CE diskette and run the alignment verifica·
tion test. The display will indicate correct or incorrect
alignment.
NOTE: Check the Head Carriage Adjustment and adjust if
necessary.
Clamp
DISKETTE UNIT - Adjustments
-35-
Head/Carriage
Pull Scale Hook
Clip
Drive band must be parallel
to pulley edge.
Carriage Bracket
Shaft.
Pulley