Memorex 660-1 User manual

MEM REX
660-1
Disc Storage Drive
Maintenance Manual
660-1 .20-00

Publication Number 660-1 .20-00
Part Number 804468
June 1975 edition
The information in this publication is subject to periodic revisions and to
updates by Publications Bulletins. A bulletin is identified as Publication
Number 660-1 .20-00XX, where "XX" equals "01" for the first bulletin
released.
A readers' comments form is provided at the back of this publication. If the
form has been removed, please send comments to Memorex Corporation,
Department 6940, MIS 14-07, San Tomas at Central Expressway, Santa
Clara,
California 95052.
This publication obsoletes Publication Number 69-04 and Publication
Number 4428.
c 1975, MEMOREX CORPORATION

Section
1
TABLE OF CONTENTS
INTRODUCTION
1 .1
1.2
1.3
1.3.1
1.3.2
1.3.3
GENERAL
............................................... .
STORAGE
MEDIA ........................................ .
BASIC DRIVE OPERATIONS .............................. .
Seek
.................................................. .
Write Operation ....................................... .
Read Operation
........................................ .
Page
1 -1
1 -1
1-2
1-2
1-2
1-4
1-S
2 MACHINE DESCRIPTION ........................................ 2-1
2.1
2.2
2.3
2.3.1
2.3.2
2.3.3
2.3.4
MACHINE PARAMETERS ................................. .
MACHINE ASSEMBLIES AND PARTS ..................... .
FUNCTIONAL AREAS .................................... .
Cabinet and Cooling System
............................ .
Input/Output (I/O) Interface ............................ .
Operator Control Panel
................................. .
POSitioning and Spindle Drive
Mechanisms .............. .
2-1
2-3
2-7
2-7
2-9
2-14
2-16
3 INSTALLATION.................................................. 3-1
3.1
3.2
3.3
3.3.1
3.3.2
3.4
3.S
3.S.1
3.S.2
3.S.3
3.6
GENERAL
............................................... .
UNPACKING AND INSPECTION ........................... .
REPACKING FOR RESHIPMENT OR STORAGE ............ .
Preparation
............................................ .
Packaging
............................................. .
ENVIRONMENT .......................................... .
PRIMARY POWER SOURCE DETERMINATION ............. .
660-1 A (60-Hz
Model Drive) ............................ .
660-1 B (SO-Hz
Model Drive) 220 Vac Operation ......... .
660-1 B (SO-Hz
Model Drive) 380 Vac Operation ......... .
INSTALLATION .......................................... .
3-1
3-1
3-4
3-4
3-4
3-6
3-6
3-6
3-7
3-8
3-9
4 THEORY OF OPERATION........................................ 4-1
4.1 INTERFACE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.1
Timing................................................. 4-1
4.1.2 Interface Lines
.......................................... 4-7
4.2 POv'VER UP ............................................... 4- i 0
4.3 FIRST SEEK .............................................. 4-11
4.4 SEEKS OTHER THAN FIRST SEEKS ........................ 4-13
4.S READ/WRITE OPERATION ................................ 4-14
4.S.1 Write Operation ........................................ 4-1S
4.5.2 Read Operation ......................................... 4-17
jii

Section
4.6
4.6.1
4.6.2
Page
POWER DOWN ........................................... 4-1 8
By
Operator ............................................ 4-1 8
By
Controller ........................................... 4-18
5 ADJUSTMENT AND REPLACEMENT PROCEDURES ............ 5-1
5.1
5.2
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.4
5.4.1
5.4.2
5.4.3
5.5
5.5.1
5.5.2
5.5.3
5.5.4
5.5.5
5.5.6
5.6
5.6.1
5.6.2
5.7
5.7.1
5.7.2
5.8
5.9
5.10
5.10.1
5.10.2
5.11
5.12
5.13
5.14
5.15
5.15.1
5.15.2
5.15.3
5.15.4
5.15.5
5.15.6
5.16
5.17
SAFETY PRECAUTIONS .................................. .
TOOLS AND TEST EQUIPMENT ........................... .
POWER SUPPLY ADJUSTMENTS ......................... .
±
15V +5V Power Supply ............................... .
±36-Volt Supply ....................................... .
±
15-Volts Servo Power Supply ......................... .
+5-Volts Servo Power Supply ........................... .
INDEX TRANSDUCER BLOCK ALIGNMENT ................ .
Transducer to Index Disc Gap (Radial Adjustment) ....... .
Index Transducer Circumferential Alignment Check ...... .
Index Transducer Circumferential Alignment ............ .
CYLINDER TRANSDUCER REQUIREMENTS
AND ADJUSTMENTS ..................................... .
Alignment Specifications ............................... .
Transducer Oscillator Check ............................ .
Transducer Alignment Check ........................... .
Cylinder
Transducer Partial Realignment Procedures ..... .
Transducer Adjustment Procedure ...................... .
Detent Plunger Clearance .............................. .
SERVO ADJUSTMENTS .................................. .
Servo Power Supply ................................... .
Servo Adjustment Procedure ........................... .
OFF-LINE HEAD
ALIGNMENT ............................. .
Head
Alignment Check ................................. .
Head
Alignment ....................................... .
HEAD UNLOAD CAM REPLACEMENT ..................... .
HEAD-ARM ASSEMBLY REPLACEMENT .................. .
SPINDLE DRIVE MOTOR REPLACEMENT .................. .
Motor Plate Assembly RemovaI ......................... .
Motor Plate Assembly Installation ...................... .
SPINDLE DRIVE BELT REPLACEMENT .................... .
SPINDLE ASSEMBLY REPLACEMENT ..................... .
TORSION ROD REPLACEMENT ........................... .
INDICATOR LAMP REPLACEMENT ........................ .
BOBBIN CHANGE PROCEDURE ........................... .
Disassembly ........................................... .
Preassembly
........................................... .
Soldering .............................................. .
Assembly .............................................. .
Testing
................................................ .
Final
Assembly ........................................ .
CARRIAGE WAY AND LINEAR MOTOR
ALIGNMENT PROCEDURE ................................ .
CARRIAGE LOAD FORCE (PRELOAD) ADJUSTMENT ....... .
iv
5-1
5-2
5-3
5-3
5-5
5-6
5-6
5-6
5-6
5-8
5-8
5-9
5-9
5-10
5-10
5-15
5-17
5-19
5-19
5-19
5-20
5-22
5-22
5-24
5-27
5-27
5-29
5-29
5-29
5-31
5-32
5-33
5-34
5-35
5-35
5-37
5-38
5-38
5-39
5-40
5-40
5-43

Section Page
6
SCHEDULED AND UNSCHEDULED MAINTENANCE ............ 6-1
6.1
6.1.1
6.1.2
6.1.3
6.1.4
6.1.5
6.1.6
6.1.7
6.1.8
6.1.9
6.1.10
6.1.1 1
6.1.12
6.1.13
6.1.14
6.1.15
6.1.16
6.1.17
6.2
APPENDIX
PREVENTIVE MAINTENANCE ............................. .
Air Filter Inspections ................................... .
Pack
Shroud Cleaning .................................. .
Head
Inspection and Cleaning .......................... .
Detent Pack Cleaning and Pawl Lubrication ............. .
Spindle Oiling ......................................... .
Detent Pawl Oiling ..................................... .
Spindle Brake Oiling ................................... .
Carriage
Way Oiling ................................... .
Air Filter Replacements ................................ .
Plunger IPawls Clearance Check ........................ .
Detent Reed Cleaning .................................. .
Detent Actuator IWiper Oiling .......................... .
Plunger IWasher Oiling ................................. .
Detent Pivot-Block/Wick Oiling ......................... .
Absolute Filter Replacement ............................ .
Prevention, Recognition, and Recovery
from HOI ........ .
Linear Tachometer Maintenance ........................ .
TROUBLESHOOTING ..................................... .
6-1
6-2
6-2
6-2
6-3
6-3
6-3
6-3
6-3
6-4
6-4
6-4
6-4
6-4
6-4
6-4
6-4
6-7
6-8
A LOGIC STANDARDS AND INTEGRATED CIRCUIT INFORMATION A-l
B LOGIC DESCRIPTIONS ........................................... B-1
GLOSSARY
A LOGIC SIGNAL GLOSSARY
GA-l
B GENERAL GLOSSARY .......................................... GB-1
v

Figure
1 -1
1-2
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11 a
2- i i b
2-12
2-13
2-14
2-15
2-16
2-17
2-18
2-19
2-20
2-21
3-1
3-2
4-1
4-2
4-3
4-4
5-1
5-2
5-3
5-4
5-5a
5-5b
5-6a
5-6b
5-7
5-8
5-9
LIST OF ILLUSTRATIONS
Page
SYSTEM CONFIGURATION ........................................ 1-1
MEMOREX MARK VI DISC PACK .................................. 1-3
TIMING DIAGRAM ................................................ 2-1
MACHINE ASSEMBLIES AND PARTS .............................. 2-3
CABINET DIMENSiONS............................................ 2-7
DC POWER SUPPLY AND LOGIC FILE DOORS ..................... 2-8
COMMUNICATION LINES .......................................... 2-11
OPERATOR CONTROL PANEL ..................................... 2-15
LINEAR POSITIONING MOTOR .............................. , ..... 2-16
HEAD MOUNTING CONCEPT ...................................... 2-17
READ/WRITE AND ERASE POLES ................................. 2-19
DOUBLE DETENT PAWL AND CYLINDER TRANSDUCER ............ 2-20
SPRING-LOADED DETENT PAWLS AND DETENT ACTUATOR ....... 2-21
CLOSE-UP OF CYliNDER TRANSDUCER, DETENT PAWL,
AND RACK TEETH
.............................................. 2-21
CYLINDER TRANSDUCER, PRIMARY AND SECONDARY PAIRS
...... 2-22
CYLINDER TRANSDUCER OUTPUT WHEN COUNTING ............... 2-23
HEADS RETRACTED/EXTENDED SWITCH .......................... 2-24
INDEX TRANSDUCER ............................................. 2-25
COIL AND SLOT RELATIONSHiP ................................... 2-26
DISC CONFIGURATIONS .......................................... 2-26
INDEX SECTOR RELATIONSHIPS .................................. 2-27
SPINDLE DRIVE SYSTEM .......................................... 2-28
MECHANICAL SPINDLE LOCK ..................................... 2-28
PACK-ON SWITCH AND SPINDLE GROUND ........................ 2-29
DRIVE PACKING CRATE ........................................... 3-2
DRIVE UNPACKING MATERIALS ................................... 3-5
GENERAL TIMING DIAGRAM ...................................... 4-2
READ/WRITE COILS AND GAP .................................... 4-15
BIT GENERATION BY FLUX REVERSAL ............................ 4-16
SIDE TRIM ERASE CONCEPT ...................................... 4-17
INDEX TRANSDUCER WAVESHAPE ................................ 5-7
PULSE BURST .................................................... 5-8
INDEX TRANSDUCER ............................................. 5-9
TRANSDUCER OUTPUT ........................................... 5-9
RACK PAWLS AT CYLINDER 000 .................................. 5-12
RACK AND CYLINDER TRANSDUCER AT CYLINDER 202 ............ 5-12
CYLINDER COUNT LOCATION WAVEFORM ........................ 5-14
WAVEFORM OF CYLINDER COUNT LOCATION EXPANDED ......... 5-14
CYLINDER TRANSDUCER ADJUSTMENT DETAILS .................. 5-16
POWER RATE WAVEFORMS ...................................... 5-20
ERROR AMPLIFIER OUTPUT ....................................... 5-21
vi

Figure Page
5-10 HEAD ALIGNMENT READ SIGNAL AT ONE REVOLUTION .......... 5-23
5-11 HEAD-ARM MOUNTING CLIPS AND ALIGNMENT SLOTS .......... 5-26
5-12 PRELOADING THE HEAD-ARM ASSEMBLY FOR INSTALLATION ... 5-28
5-13 DRIVE MOTOR AND MOUNT ASSEMBLY ......................... 5-30
5-14 BRAKE PAWL-TO-SPINDLE PULLEY CLEARANCE .................. 5-32
5-15
PACK-ON SWITCH-TO-SPINDLE CLEARANCE ...................... 5-33
5-16 DECK PLATE ASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-36
5-17 CARRIAGE WAY ALIGNMENT .................................... 5-42
5-18 CARRIAGE LOAD FORCE ADJUSTMENT .......................... 5-44
6-1 TROUBLESHOOTING FLOWCHART ................................ 6-9
A05-1 SPEED DECODE, VELOCITY VS. CAR-PAR DIFFERENCE .......... A05-2
B06-1 DETENT PAWL, DETENT RACK, AND CYLINDER
TRANSDUCER LOCATIONS
.................................... B06-2
B06-2 CYLINDER TRANSDUCER COUPLING ............................. B06-3
B06-3 ADDED TRANSDUCER SECONDARY OUTPUTS ................... B06-4
B06-4 STROBE PULSE RELATIONSHIPS ................................ B06-5
B06-5 TRANSDUCER AMPLIFIER TIMING RELATIONSHIPS ............... B06-6
B06-6 RESTORE INITIALIZATION ....................................... B06-8
PS-1 C12 DECAY VOLTAGE ........................................... PS-5
LIST OF TABLES
Table Page
2-1 BASIC MACHINE PARAMETERS ................................... 2-2
2-2 POWER CONNECTIONS ........................................... 2-12
2-3 BUS CABLE CONNECTIONS ....................................... 2-12
VII

1.1 GENERAL
SECTION 1
INTRODUCTION
The Memorex 660-1 Disc Storage Drive is a direct access disc storage unit. It reads and
writes information on Memorex Mark VI, IBM 2316, or equivalent disc packs.
The
disc pack serves as permanent or temporary information storage media which can
be written on by one drive, removed and stored, and then installed on another drive with
no loss of compatibility.
To record (write) and recover (read) information, a disc pack is installed on a 660-1 disc
drive. The drive is responsible for performing the three basic operations: seek, read, and
write. To do this, it rotates the disc pack at the required speed (2400 rpm ±2%), selects
one of 20 read/write heads for an operation, and positions it to the prescribed track on
the disc surface (all 20 heads position to the same cylinder simultaneously, but only one
head is selected to read or write at a time). The drive allows the controller to synchronize
read/write operations by referencing to an index on the disc pack.
The
660-1 drive receives commands and data from the central processing unit through a
controller. Up to eight drives can communicate with the same controller. Figure 1-1 is a
simple block diagram showing the system configuration when more than one drive is
connected to a single controller.
A
A
A - UNIT CABLES
B BUS CABLES
C AC CONNECTIONS
TO
CENTRAL
PROCESSOR
CONTROL
UNIT
C
A
C
B
A
A
C
660~ 1 660~ 1
DRIVE B DRIVE
A
A
B
~DRIVE
W
FIGURE 1-1. SYSTEM CONFIGURATION
660-1 .20-00-6/75
1 -1

AC power is supplied externally and, in the typical installation, also comes from the
controller (as shown in Figure 1-1). There are two configurations of the 660-1 drive (A
and B) to accommodate either 60- or 50-Hz power supplies. Details of AC power
requirements are given in Section 2.3.2.1.
The 660-1 drive includes a self-contained DC power supply and does not depend on the
controller for DC power (except for special termination power which is supplied by the
DC line from the controller).
Standard voltage levels on 660-1 interface connectors are +5 volts for logical zero and 0
volts for logical one. Exceptions to this are identified in the appropriate pin connection
lists in Section 2.3.2.
1.2 STORAGE MEDIA
Memorex Mark VI, IBM 2316, or equivalent disc packs serve as the storage media for the
drive. Figure 1-2 shows the recording discs, slotted index disc on the bottom of the pack,
and top and bottom protective pack covers.
Each pack consists of eleven aluminum discs which are coated with a magnetic oxide
and mounted 0.4 inches apart on a common hub. Information is recorded on the 20
inner disc surfaces in the form of polarized magnetic particles called bits. The bits are
recorded on 203 concentric circles (track 000 to track 202) on each disc surface. Since
corresponding tracks on all 20 surfaces are vertically aligned, they are considered
information cylinders: there are 203 cylinders per pack. Cylinders 200, 201, and 202 are
ordinarily reserved as spares under the control of initialization routines.
A Memorex Mark VI or IBM 2316 disc pack IS installed on a drive by raising the cabinet
cover and lowering the disc pack onto the spiindle. The disc pack is secured to the
spindle by twisting the pack's handle clockwise. When the disc pack is secured, its cover
can be removed, the cabinet cover closed, and the machine started by pressing the
START switch on the operator control panel. Interlocks prevent the drive motor from
starting until the pack cover has been removed and the cabinet cover closed.
1.3 BASIC DRIVE OPERATIONS
1.3.1 Seek
1.3.1 .1 First Seek (To Cylinder 000)
When the START switch on the operator control panel is pressed (assuming that the
drive is connected to a controller and that its main power switch is closed), power is
supplied to the spindle drive motor and the disc pack begins rotating. Once the discs
reach 70% of the rated speed, the 20 read/write heads are positioned to cylinder 000
(home position) in a first seek sequence. This begins with a forced forward seek which is
not completed as in a normal seek. Instead, the carriage moves all the way out to the
forward stop and when it comes to rest against the forward stop, it makes a normal
reverse seek to home position (cylinder 000).
After the detent engages, the drive signals the controller that it is ready for further
instructions. Normally, this would mean a seek command to some cylinder where one
head would be selected to read or write information.
660-1.20-00-6/75
1-2

--
FIGURE 1-2 . MEMOREX MARK VI DISC PACK
660 -1. 20 -00-6 / 75
1-3

1 .3.1.2 Seeks Other Than First Seek
The controller initiates a seek by sending the address of the cylinder scheduled for the
next seek to the drive where that address is compared with the address of the cylinder at
which the heads are presently positioned. The computed difference between the two
addresses represents the number of cylinders the heads must travel. Comparison logic
also determines the direction in which the heads must move. Once the cylinder
scheduled for the next seek has been selected, the controller sends the address of the
head to be selected after the proper cylinder is reached.
Meanwhile, the difference count is converted by the drive into an analog voltage which
powers the linear positioning motor. Before the difference count voltage reaches the
linear positioning motor, it is compared with a speed sense voltage supplied by a
tachometer located in the positioning motor. This comparison is made by a servo
amplifier to control the voltage supplied to the pOSitioning motor so that the access
speed
of the heads is controlled.
The
detent is then picked, a 1OO-msec delay is started, and the linear pOSitioning motor
moves the heads to the new cylinder. The purpose of the delay is to provide a time check
on the positioning system. If the carriage does not reach the new cylinder and detent
within the 100 msec, a seek incomplete Signal is sent to the controller.
During a normal seek, the position of the heads is monitored constantly by a cylinder
transducer which sends a pulse to the present address register each time a new cylinder
is reached by the heads. Each pulse increases or decreases (depending on direction of
travel) the present address by one, which causes the difference count to decrease. When
the difference count reaches zero, the detent engages and the heads stop at the
prescribed cylinder.
After the damping delay times out, the drive signals the controller that it is ready for a
read
or write operation.
1 .3.2 Write Operation
Writing is performed by a magnetic recording head which flies close to the surface of the
disc while the disc rotates rapidly under or over it.
The
controller sends data to the drive using the double-frequency nonreturn-to-zero
technique. Clock pulses supplied by the controller synchronize recording of the data
pulses. Every
400 nsec (called a bit cell time) a clock pulse is recorded. If no other pulse
is recorded
between two clock pulses, that bit cell time represents a logical zero. Two
pulses recorded during a bit cell time (one pulse each 200 nsec) represents a logical one.
The pulses are recorded as
magnetic-flux reversals in a track 0.007-inches wide. Two
erase poles, which follow the read/write gap by 0.005 inches, trim previously written
data from the sides of a written track. This process is called side trimming and allows for
deviation in head positioning by reducing fringe pickup from tracks adjacent to the one
being used. The
final width of a newly recorded track is 0.006 inches.
The data track
remains on the disc surface where it can be read at any time until it is
erased by
new data.
660-1.20-00-6/75
1-4

1 .3.3 Read Operation
The same head poles used to write the data track are used to read it. The magnetic-flux
changes, recorded on the disc surface, cause current reversals in the two center-tapped
read coils. The current reversals are converted to an output signal which is transmitted
to the controller. The recorded clock pulses serve as a built-in clock for the transmitted
data.
660-1.20-00-6/75
1-5