MPI 40 Series - Preliminary Troubleshooting Steps; Drive Wont Step or Steps Erratically; Drive Motor Wont Rotate

5.2 PRELIMINARY TROUBLESHOOTING STEPS
The following preliminary steps should be performed first when a
suspected malfunction occurs:
A. Check for proper operation of controlling device and interface to
disk drive.
B. Check for proper supply voltages to the printed circuit board
assembly (refer to figure 3-2).
c. Check for proper insertion of terminator.
D. Check for proper programming of drive select and configuration
jumpers (refer to section 6).
5.3 DRIVE WON'T STEP OR STEPS ERRATICALLY
A. Verify that head cable(s) do not interfere with carriage movement.
B. With DIRECTION input low, apply stepping pulses and monitor
stepper motor control logic for proper signals as shown by timing
diagram, Figure 3-7.
C. In order to step, gate Ul5 pin 6 must be a logic low.
D. If signals measured are as shown by Figure 3-7, replace the
stepper motor (refer to paragraph 4.5.8).
5.4 HEAD/CARRIAGE OSCILLATES AT TRACK 00 (RESTORE ERROR)
A. Position the head/carriage to extreme rear of drive.
B. Check J5-12 for a high level.
track 00 sensor.
If it is not high, replace the
C. If J5-12 is high, check track 00 logic for correct signals.
5.5 DRIVE MOTOR WON'T ROTATE
A. Verify proper connection of Pl and P2 on the Spindle Speed Control
PCBA.
B. Verify Jqmper connection B2 - C2 on control electronics PCBA is
made. Check for a logic low at U28-9 and U20-2.
c. The MOTOR ON signal to the Spindle Speed Control PCBA must be a
low level for the drive motor to rotate. Verify a logic low at
Jl-4 of the Spindle Speed Control PCBA.
D. Verify +24v on Jl-1.
E. Check J2-ll of the Spindle Speed Control PCBA for approximately
+24v. If present replace the drive motor (refer to paragraph
4 .5. 7). If not present replace the Spindle Speed control PCBA
(refer to paragraph 4.5.1).
5-2