MPI 51 User manual

FLEXIBLE
DISK DRIVE
MODEL
PRODUCT
MANUAL
Revision 3
MICRO PERIPHERAlS INC.

PROPRIETARY NOTICE
Information contained in this manual is copyrighted, and may
not
be duplicated in full or in part by any person without prior
written approval from Micro Peripheral,. Inc. (MPI)
The purpose of thi' manual i, to provide the user of MPI', Model
51/52 Flexible Disk Drives with adequately detailed documenta-
tion necessary for efficient installation, operation, maintenance.
and ordering of spare parts for the equipment supplied.
Every effort has been made to keep the information contained in
this manual current and accurate as of the date of publication or
revision. However, no guarantee is given or implied that the
manual
is error free, or that it is accurate with regard to any
particular specification.
Publidt«i April 1980
"CAD P£iU'IEfW.S tC.
9754 DtHJfing Allflnue
ChllttwortIJ. C"/iforni,, 9131'
12r3J 709-4202
TWX: 9/0494-/2/3

TABLE OF CONTENTS
· . ..
1-3
Page
1-1
1-1
•1-1
1-2
• • 0 • • •
·. . ..
·. . . .
· . . . .
·...
Introduction ••••
Purpose of Equipment
Physical Description
Functional Description.
Specifications
- GENERAL DESCRIPTION SECTION
1.0
1• 1
1.2
1 .3
1.4
SECTION 2 - INSTALLATION AND CHECKOUT
Flexible Diskette Removal
Flexible Diskette Loading
•2-1
•
•• 2-1
•2-1
• • • 2-3
o02-3
• • • • 2-4
•2-4
•••••2-4
• • • 0 • •2-4
•2-4
•2-5
o2-5
•2-6
·...
Operation
Coo 1i ng • • • • •
Input/Output Cable.
DC Power • • • • • 0 •
Introduction.
Unpack i ng
Installation
Hardware • •
Dust Cover •
2.8. 1
2.8.2
2.8.3 Diskette Handling Recommendations
Initial Checkout. • • •• • •••••••
2.0
2. 1
2.2
2.3
204
2.5
2.6
2.7
2.8
2.9
SECTION 3 - INTERFACING REQUIREMENTS
3.0
Introduction
...··...·
3-1
3.1
Input Lines ······ ·
3-1
3. 1•1 Line
Termination
··· ·•·
3-1
3. 1.2 Programmable Shunt ······ ·
3-1
3. 1.3 Drive
Select 1
to
4···· · ·· 3-2
3.1.4
Motor
On
.····•·
3-2
3. 1 .5
Direction
Select
····•·•
3-3
3.1.6
Step
.•.······•·
3-3
3.1.7
Write
Gate · · ····0...···•·
3-3
3. 1.8
Write Data ······
3-3
ii

TABLE OF CONTENTS (Continued)
SECTION 3 - (Continued) Page
3.1.9 Side Select. •••••• • •• 3-3
3.1.10 In Use (optional feature) • • •• 3-4
3.2 Output Lines •• 0 • 0 • • • • • • • • • • •••• 3-4
3.3
3.4
3.2. 1
3.2.2
3.2.3
3.2.4
Connector J2
Connector
Jl
Track 00 • • • • • • • • 3-4
Index/Sector •3-4
Write
Protect •3-4
Read Data • • • • • • • 3-6
. . . . . 3-6
. • • • . . . .3-6
SECTION 4 - THEORY OF OPERATION
4.0 Introduction. • • • • • • • • • 4-1
4. 1 How To Use The Drawi ngs ••••• 4-1
402General
Description ••• 0 • • • • • ••• 4-2
4.2.1 Head Positioning Control •• 4-5
4.2.2 Track 00 Sensor ••••••••••••••• 4-5
4.2.3 Spindle Drive Control •0 • • • 4-6
4.2.4 Index Sensor •• • • • • • • 4-6
4.2.5 Head Load Mechanism. •4-6
4.2.6 Side Selection • • • • • • 4-7
4.2.7 Data Recording and Retrieving. • •••• 4-7
4.3 Detailed Descriptions •• • • • • • • • • • 4-10
4.3.1 Power up/Power down Logic •••• 4-10
4.3.2 Stepper Motor Control Logic. •••• •4-11
4.3.3 Track 00 Logic • • • • • • • •• 4-12
4.3.4 Drive Motor Control Logic. •4-14
4.3.5 Index Logic ••••• 4-16
4.3.6 Head Load Logic •0 • • • • • • • 4-16
4.3.7 Side Select Logic. • • • • • • • • •• 4-17
4.3.8 Write Protect Logic •4-18
4.3.9 Write/Erase Logic. • ••• 4-19
4.3.10 Read Logic • • • • • • ••• 4-19
iii

TABLE OF CONTENTS (Continued)
SECTION 5 - MAINTENANCE AND TROUBLESHOOTING
Page
5.5.4
5.505
5.0
Introduction 0 • • • • .5-1
5.1 General Information •••• •• •• .0.5-1
5.2 Tools Required. • • • • • • • • • • • 5-2
5.3 Preventive Maintenance. •• • • • • • • • • 5-2
5.3.1 Read/Write Head(s) and Load Pad Inspection • 5-2
5.4 Replacement Procedures • • • 5-3
5.4.1 Printed Circuit Board Assembly (PCBA). •5-8
5.4.2
Shield Assembly ••••••••••••••• 5-8
5.4.3 Right-Hand Guide/Write Protect Assembly ••• 5-8
5.4.4 left-Hand Guide Assembly ••• • • • • 5-9
5.4.5 Front Panel Bezel and
Activity LED ••••• 5-10
5.4.6 Cone Assembly. • • • • • • • •• 5-10
5.4.7
Carrier Assembly ••••• • 5-12
5.4.8 Index/Load Boss. • ••••• 5-13
5.4.9 Solenoid • 5-14
5.4.10 Drive Motor. • ~ • 5-15
5.4.11 Track 00 Sensor ••• 5-15
5.4.12 Door Button Assembly • • • • • 5-16
5.4.13 Stepper Pulley/Band Assembly •0 • • 5-16
5.4.14 Stepper Motor. • • • • • • • • • • •• 5-20
5.4.15 Head/Carriage Assembly 0 0 •••• 5-20
5.4.16
Ejector Assembly •••••••• 5-21
5.4.17 Spindle Bearings •••••••••••• 5-21
5.4.18 Head load Pad Assembly ••••••••• 5-25
5.4.19 Harness Assembly • • • • •••• 5-25
~.5 Troubleshooting Guide •• ••••••••••• •• 5-28
5.501 Prel iminary Troubleshooting Steps • 5-28
5.5.2 Drive Won't Step or Steps Erratically •••• 5-28
5.5.3 Head/Carriage Oscillates at Track 00
(Restore Error) • • • • • • ••••••• 5-29
Drive Motor Won't Rotate •••••••• 5-29
Head Will Not load •••• • • • • • • • 5-29
iv

TABLE OF CONTENTS (Continued)
SECTION 5 - (Continued) Page
• 5-31
•5-32
. • • 5-32
•5-32
Bad Index Output ••••• • • • 5-29
Bad Write Protect Output ••••••• 5-30
Activity Indicator Does Not Light. • • • 5-30
Read Errors--All Tracks. • • •••• 5-30
Read Errors--Random Tracks • 5-31
Read Error-Inside Tracks ••••••••••• 5-31
Cannot Read Prewritten Data; Can Read
Self-Written Data •••• 0
Cannot Write Data.
Erase Bad •0 •
Drive Speed Unstable
5.5.13
5.5.14
505.15
5.5.6
5.5.7
5.5.8
5.5.9
5.5.10
5.5.11
5.5.12
SECTION 6 - ADJUSTMENTS AND MEASUREMENTS
6.0 I ntroduct i on • • 6-1
6.1 Tools Required. •••••••• • ••• 6-1
6.2 Radial-Track Alignment. • 6-1
6.3 Index-To-Data Ali gnment •••• •6-4
6.4 Track 00 Sensor Alignment •••••• 00 •••• '. 6-5
6.5 Speed Control Adjustment
••• • • • • • 6-5
6.6 Track
00 End Stop Adjustment •6-5
6.7 Drive
Belt Adjustment •••• • • • • •••••• 6-6
6.7.1 Mylar (Yellow) Drive
Belt Adjustment •• 6-6
6.7.2 Neoprene (Black) Drive Belt Adjustment •6-6
6.8
Ejector Latch and Ejector Latch Release Adjustments •6-8
6.8.1
Ejector Latch Adjustment •••• • • 6-8
6.8.2 Ejector Latch Release Adjustment •6-8
6.9 Compliance
Measurement. ••••• ••6-8
6.10
Erase Measurement • • • • • • 6-9
6~11 High Frequency Playback Measurement •6-9
SECTION 7 - TRACK FORMAT AND DATA RECOVERY
Write Precompensation
7.0
7.1
I nt roduct ion • • • .... . . . . .....
. . . .7-1 ••• 7-1
v

TABLE OF CONTENTS (Continued)
SECTION 7 - (Continued)
7.2
7.3 Data Recovery
••••••••••
Track Format--Timing Considerations
.........
...
Page
••• 7-1
.7-1
APPENDIX A - SPARE PARTS LIST •••••
APPENDIX B - DRAWINGS AND SCHEMATICS
APPENDIX C - SIGNAL NAME DEFINITIONS
vi
• • • • • • • •A-l
• • • • • • • • • • • •B-1
• • • • • • • • C-1

LIST OF ILLUSTRATIONS
... . . . . . ......
Wave Forms in Read Sequence ••••••
Stepper Motor Control Timing •••••
Mo tor Con tro1 Tim i ng • • • • • •
Write Timing • • • •••
PAGE
2-2
2-6
3-5
3-5
3-5
3-5
3-5
3-5
3-5
3-5
3-6
3-6
3-7
3-7
3-8
4-3
4-4
4-4
4-4
4-10
4-10
4-13
4-15
4-20
4-22
5-4
5-6
5-11
5-17
5-18
5-22
., .
• • • 0
;, .
.. . .
o • •
·.....
·...
·.
. . ......
....
...... . ..
.....
. . ..
.. . .
• • 0 •
...
Ejector Assembly •••••••
Read Timing ••••••
Top View Disk Drive •••••
Bottom View Disk Drive
Activity Indicator Assembly
Door Button Assembly
Stepper Pulley/Band Assembly
Outl
ine and Mounting Dimensions
Diskette Orientation
Track Access Timing.
Read Initiate Timing ••••••
Read Signal Timing •••• • •••
Write Initiate Timing. • ••••
Write Data Timing. • • • •••
General Control and Data Timing Requirements (head
load
solenoid is activated with drive select)
Index Sector Timing (Soft Sector) •••••
Index Sector Timing (Hard Sector) ••••
DC Power Connector, J2 •••••••
Jl Connector Dimensions.
Interface Signals -51/52 •
Shunt
Configuration ••••
Write Protect Option •••
Functional Block Diagram
Stepper Motor Logic •••
Read/Write Logic ••••••••
Drive Motor Control Logic ••
Basic Recording Technique ••
FIGURE
2-1
2-2
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
5-1
5-2
5"~
5-4
5-5
5-6
vii

FIGURE
5-7
6-1
6-2
6-3
6-4
6-5
7-1
B-1
LIST OF ILLUSTRATIONS (Continued)
PAGE
Spindle Assembly ••••• 0 • • • •••• 5-23
Radial Track Al ignment Pattern. • • • • • • • 6-3
Index-to-Data Alignment Pattern •0 • • • 6-4
Ejector Block and Latch - top view. • ••••• 6-7
Carrier arm - top view. • • • • • • • • •• 6-7
Ejector Assembly. • • • • • • •• 6-7
Typical Track Format. • •••• 7-2
PCBA Component Layout • • • • • • • • • • B-2
viii

TABLE
1-1
1-2
2-1
4-1
5-1
5-2
LIST OF TABLES
Data Capacity Unformatted (K Bytes) •••
Mechanical and Electrical Specifications
Recommended Connectors - Pl •••••••
Write/Read and Side Selection Conditions
Remove/Replace Adjustment Check List
Harness Assembly Wire List ••••
ix
PAGE
1-3
1-4
2-3
4-17
5-3
5-27

SECTION 1
GENERAL DESCRIPTION
1.0 INTRODUCTION
This section provides a physical and functional description, and specifications
for the Model 51/52 Flexible Disk Drives, manufactured by Micro Peripherals,
Inc. In addition to the standard features described, the fol lowing additional
features are included in all models:
"Write Protect" can be used as "Disk Installed" indication.
When using FM-encoding, an additional board can be plugged on for
data separation.
C. Termination of input signals can be either 150 ohms or split 220/330 ohms.
A.
B.
1.1 PURPOSE OF EQUIPMENT
The Model 51/52 Disk Drive is acompact disk memory device designed for random-
access data storage, data entry, and data output applications. Typical
appl ications are intelligent terminal controllers, microcomputers, word
processing systems, data communications systems, error logging, micro-program
logging, and point-of-sale terminals. Model 51/52 is designed to meet and perform
to ANSI specification.
1.2 PHYSICAL DESCRIPTION
Hodel 51/52 can be mounted vertically or horizontally. However, when mounted
.. horizontally, it is recommended that the 51/52 be positioned so that the PCBA is
on the top side. The mechanical components consist of an aluminum chassis, on
which is mounted a spindle (belt-driven by a dc motor); a stepper motor/band
combination for positioning the magnetic head assembly; and a c~ne/clutch assembly
for centering and holding the recording media under operation. Access for diskette
loading is at the front of the drive. The recording-head assembly is of a glass
bonded ferrite/ceramic structure, with lifetime expectancy in excess of 20,000
1-1

hours. The electronic circuitry is mounted on a PCBA located on top of the drive.
Power and interface signals plug directly into this board. The following basic
circuits are included:
A. Stepper motor control logic
B. Read circuit.
C. Write erase circuit.
D. Spindle motor speed control.
E. Index; Track 00 and Write Protect sensing.
F. Head load driver.
1.3 FUNCTIONAL DESCRIPTION
Model 51/52 is self-contained and requires no operator intervention during
operation. The drive consists of a media-rotating system, a head-load and
positioning system, and a write/erase and read system. When the front door
is opened, access for inserting the diskette is provided. When inserting
the diskette, all positions except in/out are controlled by physical guides
internally. Correct in/out is assured by inserting the diskette until a
"click" is heard. Closing the front door activates the cone/clutch system
which
serves two purposes in the following order:
A. Correct centering of the media.
B. Clamping the media to the spindle hub.
The
spindle hub rotates at a constant speed of 300 rpm by means of a DC motor/
t~chomet~r· and a reference in a closed-loop system. When in operation, it is
important that the head-to-media relationship be controlled. This is accomplished
by the head-load system in the following way: The media is pressed against
a reference platen which is referenced to the head and the spindle hub; and
a
pressure pad is loaded against the media on the opposite side of the head
with a force of approximately 17 gr. The recording head is positioned over the
correct track by means of a four-phase stepper motor/band direct-drive mechanism,
1-2

and its associated electronics. A one-step movement causes a one-track
.avement. With band positioning, very high step rates can be accomplished with
the 51/52 system. When a Write Protected diskette is inserted, the write protect
sensor normally disables the write/erase circuits in the drive. When writing,
a 0.00525 inches (nominal) data track is recorded, followed by a tunnel eras~ ~hilh
trims the track down to 0.0050 inches (nominal). Data recovery electronics
include a low-frequency amplifier, a differentiator. a cross-over detector.
a digital filter, and a final pulse eenerator. For FM recording a data decoder
may be added to achieve separated clock and data pulses on the 1/0 connector.
1.4
SPECIFICATI01~S
The mechanical and elpctrical specifications for the Model 51/52 Flfxible
Disk Drives are given in Table 1.2. Data capacity for the Model 51/52 Flexible
Disk Drives 1s given in Table 1.1.
TABLE 1-1
DATA CAPACITY UNFORMATTED (K BYTE~)
-- -- ----,---------------------
100(1
6.25
II
___ 1..
DOl1BLE l:E~S ITY
(MFM, MFl':)
1 - I - - 9i
i
25
00
S INGLE DENS 1TY
(FH)
PARAMETEI:
r--
91
92
9
_.~.
Tl"ack 13•13
3.13
6.
•500
t
Disk
250 5
Il
1-3

Power
Typical Power Dissipation
Media
Number
of Tracks
Trac'k Der:si ty
Rotational Speed
Average Latency
Head loading tillle
Access time
TABLE 1-2
MECHANICAL AND ELECTRICAL SPECIFICATIONS
rCHARACTERISTICS -------
.
--1
..
I
! ANSI standard 5 1/4 -inch di~kette
80/91 160/92
96 TPI
300 rpm ::t 11/2%
100 msec
35 msec
5
msec, track-to-tlack
15 msec
20,000 l'ours .
3x106
passes on a single track
2
FM, MFM, M FM
2961/5922 bpi max.
5922
fci max.
125K/250K
bits/sec.
0.5 sec
3.25 ipches (8.255 cm)
5.75 inches (14.605 em)
7.6 inches (19.30 em)
3.1 pounds (1.41 kg)
+12
VDC ± 5%, 0.7p (l.4A surge),.2V ripple
+5 VDC ± 5%, 0.4A, .1 V ripple
l1W Operation
6W Standby
40 F to 115 F (4.4 C to 46.1 C)
-40 F to 160 F (-40 C to 71 C)
20% to 80% (noneondensing)
5% to 95% (noncondensing)
-500 ft to 10,000 ft (-152.4m to 3,046rn)
-1000 ft to 50,000 ft (-304.8m to 15, 240m)
6 to 600 Hz, 0.5g
9,200 Hours
0.5 Hours
Operating Temperature
Non Operating Tempelature
Operating Hurridity
Non Operating Humidity
Operating Altitude
Non Operating Altitude
Vibration and Shock (Operating)
MTBF
MTTR
PARAMETER
Head settling time
Head life
Media life
Recording method
RecoYding density
Flux density
Data-transfer rate
Power-up Delay
Height
Width
Length
Weight
1-4

SECTION 2
INSTALLATION AND CHECKOUT
2.0 INTRODUCTION
This section provides the information and procedures necessary to place Model
51/52 Flexible Disk Drives into operation.
2. 1 UN PAC KIN G
During unpacking, care must be exercised to ensure that all tools are non-magnetic
and do
not inflict damage to the unit. As the unit is unpacked, inspect it for
possible shipping damage. All claims for this type of damage should be filed
promptly with the transporter involved. If a claim is filed for damages, save
the original packing material. Most packing material may be reuseable if
reasonable care is used in unpacking. Unpack the drive as follows:
A.
C.
D.
E.
F.
. - G.
Remove external packing material carefully.
Remove the drive from the container.
Remove internal packing materials, following instructions provided
on the package.
Ensure that front access door opens and closes, and that the head-load
arm raises when door is opened.
Ensure that bezel is secured.
Ensure that drive hub manually rotates freely.
Ensure that stepper motor/head carriage assembly is not binding at
any point, by manually moving carriage back and forth.
2.2 INSTALLATION
Due to its small size and light weight, Hodel 51/52 can be installed or mounted
in any convenient location or position. However, the drive must be installed
in a location that will prevent the 1/0 cable from exceeding 10 feet in length.
Refer to Figure 2-1 for dimensions and mounting provisions.
2-1

Bottom View
Top View
-
J(7.94 em)
~~
~t:J
I
II
I
".
I
:[
I
I
....
!
~
i
1"""'1""'\.
-
..
5.87
(14.91 em)
hU ~~ - 1,1 cq
nI ; i i
'---'
..... 1--. ,j !
I
I
I
I
5.75
( .. t .61 em)
.125
(.318 em)
~
-r
I
I
I
5.500
(13.97 em)
J
3.125
1.87
(4.74 em)
Single Interface
Connector (J 1)
±- 0.010
±. 0.020
.xxx
. xx
Unless otherwise stated,
dimensions are in inches.
Tolerances:
NOTE:
.06 typ
(.15 em)
6.32 x .31 deep
(4) mtg. holes
t=
Door
Onen Position
'"
_ ~PCB
L.I..... DC Power Connector (J2)
1 I/.. 6.32 thru mtg. holes (2 pies. each side)
3.38 I , 1
(8.59 em) ~ -f- ~ - --'-
ttl .875 (2.22 em)
.06 typ J II .. 1.87 .. ~ 3.125 ! ~
(.15cm) 14.74 em) 17.94cm) I
.31----.. 7.5 max 1(19.0 em) _J
(,79 em)
Door
Closed
Position
N
I
N
Side View
Figure 2-1: Outline and Mounting Dimensions

2.3 HARDWARE
The flexible disk drive is a precision device in which certain critical
internal alignments must be maintained. Therefore, in keeping with rigid disk
requirements, it is important that the mounting hardware does not introduce
significant stress on the drive. Any mounting scheme in which the drive is
part of the structural integrity of the enclosure is not permitted. Since
the disk drive cannot be subjected to significant stress when it is slide
mounted, this type of mounting generally satisfies the foregoing requirements.
Mounting schemes should allow for adjustable brackets or incorporate resilient
members to accommodate tolerances. Mounting schemes involving more than two
hard mounting points and a third point should be avoided.
2.4 DUST COVER
Since the flexible disk drive is not provided with a dust cover, the design of
an enclosure should incorporate ameans to prevent direct ingress of loose
items, e.g., dust, paper punch waste, etc.
Table 2-1
RECOMMENDED CONNECTORS - PI
CONNECTOR
TYPE OF
CABLE MANUFACTURER
PIN
CONTACT PIN
_.----
Twisted
Pair,
26
AMP
583717-S 1-583616-1
Fl at Cab 1e
3M "Sco tchf1ex" 3463-0001 N.A. _
.. _._--
2-3

2.5 COOLING
Heat dissipation from a single disk drive is normally 15 watts (40 Btu/Hr).
When the drive is mounted so that the components have access to free flow of
air, normal convection cooling allows operation over the specified temperature
range. When the drive is mounted in a confined environment, air flow may have
to be provided to maintain specified air temperatures in the vicinity of the
motors, PCBA, and the diskette.
2.6 INPUT/OUTPUT CABLE
Refer to Table 2-1 for cable connector part number and attachment. The
maximum cable length from connector to connector is 10 feet. All inputs and
outputs are paired, one line for function, one for ground. Figure 3-11 provides
information relative to the connector pin/signal assignments for 1/0 cable.
2.7 DC POWER
DC power to the drive is via connector P2/J2, which is located on the non-
component
side of the PCBA near the spindle motor. The drive uses +l2V DC
and +5V DC. Table 1-1 outlines the voltage and current requirements. The
connector is an AMP Mate-N-Lock Part No. 1-480424-0.
2.8 OPERATION
The Model 51/52 Flexible Disk Drive is under direct control of the interface
and power sources. No special start-up procedures are necessary. Secure both
p~wer and 1/0 connectors prior to disk loading.
2.8.1
A.
B.
Flexible Diskette Loading
Apply
DC power to drive.
Open drive door by pushing door latch button.
2-4

.c.
D.
2.8.2
A.
B.
c.
Remove diskette from its storage envelope and insert in the drive •
The index
hole must be on the left side of the jacket and the label
on the right towards the door. Push the diskette forward until a
"cl
ick" is heard. (See Figure 2-2).
Close door by pushing door down until latch secures the door.
Flexible Diskette Removal
Open the drive door by pushing door latch button. The flexible
diskette will automatically be ejected to a position where it can be
easily removed.
Always
store the diskette in its storage envelope in order to maintain
the highest data integrity.
Close drive door.
2.8.3 Diskette Handing Recommendations
Since the recorded diskette contains vital information, resonable care should be
exercised in its handling. Longer diskette life and trouble-free operation will
result if the following recommendations are followed:
A. Do not use a writing device which deposits flakes (i.e., lead or
grease pencils) when writing on a diskette jacket label.
B. Do not fasten paper clips to diskette jacket edgeso
C. Do not touch diskette surface exposed by jacket slot.
D. Do not clean diskette in any manner.
E. Keep diskette away from magnetic field and from ferro-magnetic materials
that may be magnetized.
F. Return diskette to envlope when removed from drive.
G. Protect diskette from liquids, dust and metallic substances at all times.
2-5

D.
H. Do not exceed the following storage environmental conditions:
Temperature: SOoF to 12S
QF(10°C
to SlOC)
Relative Humidity: 8% to 80%
Maximum Wet Bulb: 8SoF (29.4°c)
I. Diskette should be stored when not in use.
2.9 INITIAL CHECKOUT
The following procedure should be used to determine that the Model Sl/52 is
operational. This procedure assumes that the drive is installed, lID cable
and power are connected, and that the steps in 2.1 have been completed.
A. Apply low level signal to MOTOR ON and assure that spindle hub
rotates in correct direction (clockwise from top of drive).
B. Load the diskette and apply a head-load command to the drive. Check
that head-load solenoid actuates and indicator lights on front panel.
Select proper device address.
C. Apply stepping and direction commands to the unit.·. Verify that the
actuator steps as commanded.
Remove all command signals, turn power off and return diskette to its
storage.
Figure 2-2: Diskette Orientation
2-6