CORVUS 11MB User manual

THE CORVUS SERVICE-MANuAL
11 and20 Megabyte',Drive
***CORVUSSYSTEMs
** '

II/20MB Drive Service Manual
ERRATA SHEET
DISCLAIMER OF ALL WARRANTIES &LIABILITIES
Corvus Systems, Inc. makes no warranties, either expressed or implied, with respect to this
manual
or with respect to the software described in this manual, its quality, performance,
merchantability, or fitness for any particular purpose. Corvus Systems, Inc. software is sold or
licensed" as is:' The entire risk as to its quality or performance is with the buyer and not Corvus
Systems, Inc., its distributor, or its retailer. The buyer assumes the entire cost of all necessary
servicing, repair, or correction and any incidental or consequential damages. In no event will
Corvus Systems, Inc.
be liable for direct, indirect, incidental or consequential damages, even if
Corvus Systems, Inc. has been advised of the possibility of such damages. Some states do not
..,l1nu, tho Dvrl",,; ...... n ...... r l;n'\;bnrm nf irnnlipfi \AT;:\rr;:\nnpo;; nr liahilitip", for incidpntal or
~~~sequential damages, so the above limitati~n may not apply to you.
Every effort has
been made to insure that this manual accurately documents the operation and
servicing of Corvus products. However, due to the ongoing modification and update of the
software along with future products, Corvus Systems, Inc. cannot guarantee the accuracy of
printed material after the date of publication, nor can Corvus Systems, Inc. accept responsibility
for errors or omissions. -
NOTICE
Corvus Systems, Inc. reserves the right to make changes in the product described in this
manual at
any time without notice. Revised manuals and update sheets will be published as
needed and may be purchased by writing to:
*
**
CoRVUS
Corvus Systems, Inc.
2100 Corvus Drive
San Jose, California 95124
[phone]
Telex 278976
This manual is copywrited and contains proprietary information. All rights reserved. This
document may not, in whole or in part be copied, photocopied, reproduced, translated or
reduced to any electronic medium or machine readable form without prior consent, in writing,
from Corvus Systems, Inc.
Copyright© 1982
by Corvus Systems, Inc. All rights reserved.
Mirror® patent pending, The Corvus Concept,'" Transporter,'" Corvus OMNINET,'"
Corvus
Logicalc,'" Time Travel Editing,'" EdWord,'" Constellation,'" Corvus,'" Corvus Systems,'" Personal
Workstation,'" Tap
Box,'" Passive Tap Box,'" Active Junction Box,'" Omninet Unit'" are trademarks
of Corvus Systems, Inc.
CP/M® is aregistered
trademark of Digital Research Inc.
Apple,® Apple
II® and Apple II Plus® are registered trademarks of Apple Computers, Inc.
TRS.,.80® and Radio Shack® are registered trademarks of Tandy Corporation.
SuperBrain®is aregistered
trademark of Intertec Data Systems, Inc.
DEC,® LSI-11,® RL01 ® and RL02® are registered trademarks of Digital Equipment Corporation.
UCSD PASCAL'" is a
trademark of the Regents of the University of California.
IBM® is aregistered trademark of IBM Corporation.
Z-80®
and Z-80A®are registered trademarks of Zilog, Inc.
FCC WARNING
This equipment generates, uses, and can radiate radio frequency energy and if not installed and
used in accordance with the instruction manual, may cause interference to radio
communications. As temporarily
permitted by regulation it has not been tested for compliance
with the limits for Class A computing devices pursuant to Subpart Jof Part 15 of FCC Rules,
which are designed to provide reasonable protection against such interference. Operation of
this
equipment in aresidential area is likely to cause interference in which case the user at his
own expense will be required to take whatever measures may be required to correct
the interference.
ERRATA
PAGE 10,
section 4.3
Delete "Omninet," insert "Corvus OMNINET"'''
PAGE 45, section 8.3.6.1
Delete "Superbrain;' insert "SuperBrain®"
Delete
"Superbrain and TRS-80;' insert "SuperBrain® and TR5-80®"
PAGE 53, section 9.3
Delete" Apple II +," insert" Apple II Plus®"

CORVUS DEALER SERVICE
CORVUS SYSTEMS
11MB AND 20MB
EIGHT-INCH WINCHESTER
DISK DRIVE
SERVICE MANUAL
This document contains three types of notations. These are, in increasing order of importance, NOTE,
CAUTION, and WARNING. The NOTE indicates some action to be taken to speed or simplify a
procedure.
The CAUTION indicates that potential damage to the equipment or user data exists, and
care should be taken to avoid this. The WARNING indicates that potential harm or injury to the
service technician or operator exists, and extreme care should be taken to avoid these.

CORVUS DEALER SERVICE
TABLE OF CONTENTS

CORVUS DEALER SERVICE
TABLE Of CONTENTS
CHAPTER 1 - GENERAL DESCRIPTION
1.1 Scope of Chapter ......................................................................... .. 1
1.2
Introduction 1
1.3 Model Identification. ........................................................................ 1
1.4 Purpose of Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
1.4.1
Power Supply. .................................................................. .. 1
1.4.2
Data Backup. ................................................................... .. 2
1.5
Corvus Disk System. .......... .. .. ...................... ... . . ... . . . . ... . . .. . . . . . . ... .. . .. .. 2
1.6
Winchester Technology. . . . . . . . . . . . . . . . . . . .. . . . . . . .. ............ .. . . . . .. .. . .. . .. ... .. . .. . .. .. 2
CHAPTER 2 - INSTALLATION
2.1 Scope of Chapter. ........................................................................ .. 3
2.2
Introduction 3
2.3 Receiving aDrive .........................................................................
.. 3
2.3.1 Headlock
Mechanisms 3
2.3.2 Diagnostic
Test. ................................................................. .. 4
2.4 Installation
Considerations. ................................................................ .. 5
2.5 Daisy-Chaining
of Disk Drives 6
CHAPTER 3 - OPERATION
3.1 Scope of Chapter 8
3.2
Introduction 8
3.3
Controls. ................................................................................ .. 8
3.3.1
Front Bezel LEOs. . ... ..... .. ... .. ............ .. ... ... . ... . ... ............. ... . . ... 8
3.3.2
Front Bezel Switches. ............................................ .. .............. .. 9
3.4
Power-On Sequence 10
3.5 Environmental
Requirements 10
3.5.1 Static Electricity 10
3.5.2 Line Noise. ..................................................................... .. 10
3.5.3
Temperature 10
3.6 Periodic
Maintenance 10
3.6.1 Regular Checks
11
3.6.2 Groundstrap 11
CHAPTER 4 - DRIVE DESCRIPTION
4.1 Scope of Chapter ....................................................................... .. 12
4.2
Introduction .12
4.3
Power Supply 12
4.3.1
CSI00 12
4.3.2 CP129 12
4.3.3 CP140 12
4.3.4 CP411 16
4.4 dc
Power CahIes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16
4.5 Definition
of Terms 16
4.5.1 Disk Sealed Mechanism 18
4.5.2 Controller Firmware 18
4.5.3 Data
Storage 18

CORVUS DEALER SERVICE
4.5.4 Headlock Devices ................................................................ .. 19
4.5.5
Preamp PCA 19
4.5.6 Drive Electronics Revision 19
4.6
Power- Up 20
ru" D'T'l:D l!' 'TUrt""\DV t""\r t""\DrD "'TTt""\lll. T
...... A.A ...... .&. .& ........... v .&.&& ..... '-'.&'-.a. '-"'JL '-' ............ '-A.a..a..a.'-J .....
5.1 Scope of Chapter 21
5.2 Introduction 21
5.3 Servo Electronics 21
5.3.1 Servo Tracks 21
5.3.2 Servo Control Signals 24
5.3.3 Servo
Operation 24
5.4 Read/Write Electronics
24
5.4.1 Read Operation 25
5.4.2 Write
Operation 25
5.5 Controller/Logic Electronics 26
5.5.1 Host to Drive Handshaking Controi Signais 26
5.5.2 Controller During Seek Command 27
5.5.3 Controller During Read and Write Commands 27
5.6 Backplane /Motherboard PCA 28
5.7
Preamp PCA ............................................................................. .. 28
5.8 Paddleboard
PCA ......................................................................... .. 30
5.9 Interface PCA ............................................................................ .. 30
CHAPTER 6 - DISASSEMBLY
6.1 Scope of Chapter 31
6.2
Introduction 31
6.2.1 Tools Required ..................................................................
.. 31
6.3
Metal Cabinet 31
6.3.1 Top
Cover ...................................................................... .. 31
6.3.2 Rear
Bezel. ..................................................................... .. 31
6.3.3 Backplane
Cover 33
6.3.4 Cabling 33
6.3.5 Drive
Mechanism 33
6.3.6 Power Supply 33
6.3.7 Front Bezel 33
6.4 Stand-Alone Units ..................................................................
.. 33
6.4.1 Disassembly (CSIOO)
33
6.5 Drive Electronics Removal and Disassembly 33
6.5.1
Card Set 34
6.5.2
PCA Replacement 34
CHAPTER 7 - ADJUSTMENTS AND MAINTENANCE
7.1 Scope of Chapter 35
7. 2 Introduction 35
7.3 Power Supply Voltage Check and Adjustment 35
7.3.1 CP140 and CP411 35
7.3.1.1 Voltage Check 35
7.3.1.2 Voltage
Adjustment 36
ii

CORVUS DEALER SERVICE
7.3.2 CS100 36
7.3.2.1 Voltage Check 36
7.3.2.2 Voltage Adjustment 36
7.3.3 CP129 37
7.3.3.1 Voltage Check 37
7.3.3.2 Voltage Adjustment 37
7. 4 Servo Mechanism. ........................................................................ .. 38
7.4.1 Servo Adjustment ASM 310176 and ASM 310221 38
7.4.2 Servo Adjustment ASM 310006 40
7.5 Brake Mechanism 41
7. 5.1 Brake Adjustment ...................... .. 41
CHAPTER 8 - DEALER SERVICE DIAGNOSTICS
8.1 Scope of Chapter ......................................................................... .. 43
8.2 Introduction 43
8.3 Drive Diagnostics RevB 43
8.3.1 CRC 43
8.3.2 EXR
~. 43
8.3.3 UPD 43
8.3.4
VSN 44
8.3.5
FMT 44
8.3.6
PRM 44
8.3.6.1
MUX 44
8.3.6.2 DRIVE 45
8.3.7 SET
45
8.3.8 QUIT 45
8.4
Controller Diagnostic 45
8.4.1
General Description 46
8.4.2 Controller Diagnostic Commands 46
8.4.2.1 A) Abort Diagnostic 46
8.4.2.2 B) Macro Menu 46
8.4.2.3 C) Change Slot Number , 47
8.4.2.4 D) Download Diagnostic 47
8.4.2.5 I) Analyze Servo 47
8.4.2.6 J) Single Do Seek. ................................................... .. 47
8.4.2.7 L) Full Cylinder Loopseek 48
8.4.2.8
P) Print Quiet Summary Report 48
8.4.2.9 Q) Sector Quiet Program 48
8.4.2.10
S) Read Scan Disk ................................................... .. 48
8.4.2.11 nSingle Cylinder Seek Scan 49
8.4.2.12 X) Write Scan Disk 49
8.4.2.13 Y) Rezero Heads 49
8.4.3 Error Codes 49
8.5 Burn-In Program 49
8.5.1
C)ONT 50
8.5.2 L)IST 50
8.5.3 R)ESTART 50
8.5.4 Q)UIT 50
8.6 Read Burn-In Results 50
iii

CORVUS DEALER SERVICE
nri"p ni~on()l:;tirl:; Rpv A
AD] .8.8.1
Track Diagnostic. ......................................................................... .. 51
8.7.1 C)ONT 51
8.7.2 L)IST 51
8.7.3 R)ESTART 51
8.7.4 Q)UIT 51
51
52
RR
8.7
CHAPTER 9 - FAULT ISOLATION PROCEDURES
9.1 Scope of Chapter , . .. 53
9.2 Introduction 53
9.3 Tools .................................................................................... .. 53
9.4 Error Codes. ............................................................................. .. 53
9.4.1 Interpreting Error Codes 53
9.5 Troubleshooting Procedures 57
9.5.1 On-Site Checks 57
9.5.2 Isolate the Problem 57
9.5.3 Drive Not Ready 58
9.5.3.1 Interface 58
9.5.3.2 Controller Firmware .................................................. .. 58
9.5.3.3 Power Supply Voltages ................................................ .. 58
9.5.3.4 RESET Line 58
9.5.3.5 Drive Electronics 59
9.5.3.6 Drive Sealed Mechanism 60
9.5.4 Link Inoperative 60
9.5.4.1 Check Link Action .................................................... .. 61
9.5.4.2 Power Supply 61
9.5.4.3 CRC Test 61
9.5.4.4 Servo Test 62
9.5.4.5 Controller Firmware 62
9.5.4.6 Boot ROM 62
9.5.4.7 Interface Components 62
9.5.4.8 Drive Initialization 62
9.6 Final Adjustments and Tests 62
9.6.1 Proper Headlock Operation ....................................................... .. 62
9.6.2 CRC Test 63
9.6.3 Servo Check and Adjustment 63
9.6.4 Install and Test Mirror 63
9.6.5 RESET Line 63
9.6.6 CRC Test 0 •••••••••••••••••••••••••••••••••••• 63
9.6.7 Power Supply. .................................................................. .. 63
9.6.8 Burn-In Test 63
9.7 Troubleshooting Flowchart 65
9.8 Common Symptoms and Recommended Solutions 66
Appendix A
Appendix B
Appendix C
Appendix D
Glossary. ........................................................................ .. 72
Parts List for Eight-Inch Drives 74
PCA Compatibilities 76
Assembly and Schematic Drawings 77
Index " 144
iv

CORVUS DEALER SERVICE
LIST OF ILLUSTRATIONS AND TABLES

CORVUS DEALER SERVICE
LIST OF ILLUSTRATIONS AND TABLES
ILLUSTRATIONS
Figure Page
2-1 Manual Carriagelock Location. ............................................................. .. 4
2-2
CORCOM Unit. ......................................................................... .. 5
2-3 Rear Bezel
Components , . . . . . . . . . .. . .. ......... .... . .. .. ........... .. 6
3-1
Front Bezel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8
3-2Function Switches ........................................................................ .. 9
4-1 Stand-Alone
Drive with CS100 Power Supply 13
4-2 Stand-Alone
Drive with CP129 Power Supply 14
4-3 White
Cabinet with CP140 Power Supply 15
4-4
Data Configuration. ...................................................................... .. 16
4-5 Disk
Drive Sealed Mechanism. ............................................................. .. 17
4-6 Sector Interleaving 18
4-7 Peamp
PCA Location 20
5-1 Servo Track Relationship 22
5-2 Tri-Bit Signal 22
5-3 Corvus RevB Block Diagram 23
5-4 Read/Write
PCA Jumper Location 25
5-5
NRZ and MFM Data Formats 26
5-6 RevA Cabling 29
5-7 RevB Cabling ............................................................................ .. 29
6-1 Access Door,
Metal Package. ............................................................... .. 32
7-1 dc Power Cable Connection "35
7- 2Drive Configuration for Servicing 38
7-3 PES Signals Improperly and Properly Adjusted 39
7-4 Mechanism Adjustment ................................................................... .. 42
9-1 Location
of R3 59
9-2 PES as Result of Good and Bad Servo Tracks 61
9-3 Checking Proper Headlock Operation ....................................................... .. 64
TABLES
Table Page
1-1 Unit Address Options. .................................................................... .. 7
9-1 Decimal Disk
Error Codes 54
9-2Hexidecimal Disk
Error Codes 55
9-3 Signed Decimal Disk
Error Codes 56
v

CORVUS DEALER SERVICE
SPECIFICATIONS

Operational Specifications
Disks
per Drive
Data Surfaces per Drive
Servo Surfaces per Drive
Heads per Surface
Data Heads
Servo Heads
Number of Data Cylinders/Drive
Sectors per Track
Track
Density (TPI)
Bytes
per Sector (Formatted)
Bytes
per Track (Formatted)
Bytes
per Drive (Formatted)
Bit
Density (BPI)
Average Latency (ms)
Average Access Time (ms)
Maximum Access Time (ms)
Maximum Access Time, Single-Track (ms)
Data Transfer Rate (Kb/s)
Recording
Format
Rotational Speed (RPM)
Start Time (s)
Stop Time (s)
Physical Dimensions (White Cabinet)
Height (In/Cm)
Length (In/Cm)
Width (In/Cm)
Weight (L bs/Kgs)
Environmental Requirements
Operating Temperature (F/C)
Non-Operating Temperature (F/C)
Operating Relative Humidity (%)
Non-Operating Relative Humidity (%)
Operating Altitude (ft)
Operating Vibration (G)
Non-Operating Vibration (G)
Non-Operating Shock (G)
CORVUS DEALER SERVICE
SPECIFICATIONS
vi
11MB 20MB
23
3 5
11
1 1
3 5
1 1
358 388
20 20
300 300
512 512
10,240 10,240
10.9MB 19.7MB
5,868 5,868
8.3 8.3
35
35
65 65
6 6
648 648
MFM MFM
3,600 3,600
15 25
30 30
6.375
/16.19
23.0/58.42
14.5/36.83
48/22
50
0
to 100
0
/10
0
to 37
0
-40
0
to 140
0I
-40
0
to 60
0
10 to 80
10
to 90
-1,000
to +10,000
0.1
(5 cps linear increase to 100 cps)
1.0
(2 cps linear increase to 100 cps)
5.0
for 5ms duration

Power Requirements
Line Voltage, Domestic (VAC)
Line Voltage, Foreign (VAC)
Power Consumption (Watts)
Line
fuse (Amperes)
c__ .. ",,' 7 ..... ,,' 7
j,,'-'.L ..L.V\"I W - ..L.",""V Y
for 220V-240V
Reliability
Mean Time Between Failure (tv1TBF)
Maximum Repair Time
CORVUS DEALER SERVICE
vii
100-120, 48Hz-62Hz, Single-Phase
220-240, 48Hz-62Hz, Single-Phase
250
":1:. V
2.0
10/000+ operational hrs., vv"'ithin
above requirements
Not more than 0.5 hrs.

CORVUS DEALER SERVICE
CHAPTER 1
GENERAL DESCRIPTION

CORVUS DEALER SERVICE
CHAPTER 1
GENERAL DESCRIPTION
1.1 Scope of Chapter
This chapter outlines the purpose of the II-megabyte and 2D-megabyte disk drives. Also provided is abriefdescription
of the drive packaging and layout, and adefinition of Winchester technology. Read the manual completely before
attempting any service procedures.
1.2 Introduction
This document contains procedures and data required to service Corvus II-Megabyte and 20-Megabyte eight-inch
Winchesterdisk drives.
Corvus five-inch Winchesterdrives and floppy drives are covered in separate servicemanuals,
as are
networks and peripheralequipment. Troubleshooting and repair of all equipment will be addressed on a modular
level.
There exists two versions of the 11MB Corvus drive: the Revision A(RevA) and the Revision B(RevB). The 20MB
drive was
manufactured in aRevision Bonly. Service procedures for the eight-inch Corvus disk drives will apply to
both the RevA and RevB drives, except where noted. Specific differences will be outlined later in this manual.
Also included in this publication
is documentation on the Dealer Service Diagnostic Utility diskette supplied to each
service center.
The utilities provide for burn-in/reliability testing, adjustment, and troubleshooting of all Corvus disk
drives.
Installation and operation
of the Corvus disk drives will not becovered in detail in this document. Refer to the "Corvus
Systems Installation Guide" and "Corvus Systems User Guide" for information on these subjects.
1.3 Model Identification
The Corvus eight-inch disk drives are very similar in appearance. Before any service procedures are attempted, the
drive must be identified as to the model and serial number.
Locate
the serial number tag on the rear bezel. The following is asample serial number to be found on a Corvus
eight-inch drive:
142-C350/M
and is decoded below:
14
represents the week of manufacture (14 for March/April)
2
represents the year of manufacture (2 for 1982)
C
represents a20 MB eight-inch drive (B for a11MB)
350
represents the serial number of that weeks' manufacture
/M represents that the drive was shipped with an internal mirror
Whenever communicating with Corvus in reference to Corvus products, include the serial number of the equipment
involved.
1.4 Purpose of Equipment
The Corvus disk drive is ahigh-speed, intelligent mass-storage peripheral disk device designed to provide the host
microcomputer with storage of digital information for instant retrieval at the request of the host system. The Corvus
disk system consists of the disk drive with its 2-80 Intelligent Controller, power supply, host interface electronics,
34-pin interface flat-cable and
Corvus Utility diskettes.
1.4.1 Power Supplies
The power supply operates from either 110-120VAC or 220-240VAC, 50Hz or 60Hzsingle-phasepower. Early models
of the Corvus disk drive were stand-alone units. The latest model uses a white cabinet enclosure which contains the
disk mechanism, cooling fan and power supply.
1

CORVUS DEALER SERVICE
1.4.2 Data Backup
Data backup is accomplished via the Corvus Mirror. The Mirror converts the data from digital format to video format
which is then stored on video cassette tape, using one of many commercial VCRs. The Corvus Mirror option comes
internal to the drive when it is ordered. or added as an external device later. Mirror troubleshooting and repair is
covered in the Corvus Mirror Service Manual.
1.5 Corvus Disk Systems
The Corvus Mass-Storage Disk System utilizes asealed Winchester disk mechanism manufactured by International
Memories, Inc. (IMI). The drive, with its Intelligent Controller, is designed as aplug-in device, requiring minimal
software setup. Interfacing to host computers is via 34-pin flat-cable interface. Installation and setup procedures are
covered in the corresponding user guide for the appropriate computer system.
Early
versions of the eight-inch Corvus Disk System consist of the sealed drive mechanism with drive electronics, and
power supply, either separate or on a common baseplate. Some RevA and RevB drives are configured this way. Recent,
upgraded versions of the Corvus package consist of a white cabinet housing the sealed disk mechanism and drive
electronics,
power supply, Mirror (if that option is ordered), fan and cabling. Most RevB drives use this configuration.
Located in the bottom of the sealed unit, the PCA card cage contains the drive electronics responsible for servo control,
read-write controi, microprocessor interfaceicontrol. External to the drive, the interfacecard and cable transfer data to
and from the host computer.
The Intelligent Controller PCA and internal Mirror PCA can be viewed through the access door in the bottom of the
drive cabinet. Only the Mirror PCA may be removed through this door.
The RevAsealed mechanism was manufactured in II-megabyte capacities only. The RevB is manufactured in both 11-
and 20-megabyte capacities. There are no fundamental differences in the sealed mechanisms of the RevA and RevB
11MB units.
This is not to say that all 11MB units are identical. Each unit should be inspected to determine its particular
designation.
Some of the drive electronics are different and are not compatible between RevA and RevB.
All
Corvus disk mechanisms have some sort of carriage locking device which restrains the heads. Inherent in the
Winchester drive design is the necessity for the heads to rest on the platter surface when the drive is powered off.
Because
of this contact, the heads must be parked safely off of the Data Area, onto an Outer Guardband Area of the
platter surface. This is accomplished by either of two methods. Earlier versions of the drive used a manual headlock
device,
which is identified by a screw located on the side of the mechanism. Current versions of the drive use an
electromechanical headlock which automatically secures the heads after the power is removed from the drive.
L6 Winchester Technology
The Corvus disk drive uses the IMI Winchester disk mechanism. This new generation of disk drive utilizes asealed
environment, and low-load, low-mass, aerodynamically-suspended read-write heads which rest directly on the disk
surface after powerdown. It is the contaminant-free environment that allows for reduction in clearance between head
and recording media. This results in the heads riding on a18-micron cushion of air. Sincebit density is closely related to
head-media clearance and head mass, disk drives utilizing Winchester technology can achieve large storage capacities at
a premium of space.
An added
advantage of the Winchester sealed mechanism is that it requires no regular maintenance.
2

CORVUS DEALER SERVICE
CHAPTER 2
INSTALLATION

CORVUS DEALER SERVICE
CHAPTER 2
INSTALLATION
2.1 Scope of This Chapter
Installation and operation procedures for the Corvus disk system are outlined in the "Corvus Disk SystemsInstallation
Guide"and
"Corvus Disk Systems UserGuide". This chapter discusses installation of the diskdrive hardware onlyas it
applies
to environmental requirements.
2.2 Introduction
Each drive, when it is received, should be checked for shipping damage, and tested for proper function. This chapter
contains these procedures as well as those for installing single drives and multiple-drive systems.
2.3 Receiving aDrive
Any time adrive is received, severalchecks should be performed before the drive is installed at the customer site. Each
Corvus disk drive should becarefully unpacked andchecked for shipping damage. Externalevidence of rough handling
may be symptomatic
of damage to fragile mechanisms within the drive.
NOTE:
Any damage claims must be reported to the local office of the shipper so an inspection may be made, and a damage report filed.
Also, if the damaged equipment is a new product, Corvus Order Processing Department must be contacted for proper return
procedures. If the damaged equipment is a recently serviced product being returned under an RMA number (Return
Merchandise Authorization number), contact Corvus Customer Service Department for proper return procedures.
The disk drive mechanism in the Corvus Disk System is an extremely sensitivedevice. Subjecting the drive to aone-g
force (onegravity) will beamplified and
transmitted to the heads, impacting them onto the platter with a100-g force.
This necessitates very careful handling
of the drive mechanism both in shipping and operation.
When adrive
is received, check that all chipsin the Z-80 Controller PCAareseatedwell in their sockets. Chipscoming
loose during shipping account for alarge
number of failures upon receipt.
1) Locate the access door in the center of the drive basepan.
2) Remove the two allen screws and open the door. The Controller/Logic PCA is located directly behind the access
door, facing
outward.
3) Press firmly on all socketed chips, seating them securely into their sockets.
4) Replace allen screws.
2.3.1 Headlock Mechanisms
All eight-inch sealed disk mechanisms have alocking device to ensure that the heads are secured during shipment.
Early models use amanual locking device consisting
of alocking screwaccessable from the side of the mechanism. This
screw
must be used to lock the heads priorto shipping or unlock prior to use: (Turn the screwClockwise to unlock the
heads. Turn the screw Counter-Clockwise to lock the heads. Do not use excessive force when turning the headlock
screw.)
Current models use an automatic electro-mechanical headlock which secures the heads every time power is
removed from the drive.
CAUTION:
If thediskdrivehas amanual lock,the lock mustbereleased beforeanyattemptis made to operate
the disk drive. Attempting
to operate the drive before unlocking the heads will cause the servo
electronicsto be damaged. Do
not transportthe drivewith theheadsunlocked.Thiscan cause the
heads to impact onto the disk surface, damaging both,
if the unit is jarred.
Manual locking drives mustbe FULLY unlocked before use. This requires the locking screw to be
turned approximately
171/2 turns clockwise. If tension is felt, STOP IMMEDIATELY and verify that
the headsare unlocked
by tilting up the rear of thedrivemechanism (theendwiththeBackplane/
Motherboard). If the heads slide freely across the disk, the heads are unlocked.
3

CORVUS DEALER SERVICE
CAUTION: (continued)
To lock the heads, tilt up the front of the drive mechanism (the end opposite the Backplane/
Motherboard)
to return theheads to theoutsideedge of thedisksurface.Whileholdingthedrivein
thisposition,tightenthelockingscrew
by turning it counter-clockwiseapproximately 17V2 turns.If
tensionisfelt, STOPIMMEDIATELYandverifythattheheadsmove no morethan Va" when therear
end
of the drive is tilted up.
Over-tightening
or over-loosening of theheadlockscrewmayresult in destruction of theheadlock
mechanism, rendering the sealed
unit defective. Care mustbe exercised whenever tightening or
loosening this screw.
f-- ~---.;::;C=-=iARRIAGE LO;=.C~K ~ ____f
t-------- ...... -U-N-LO-C-K~ ( ~ ) PL-O-C-K-....."I------t
L_ ~O_ N~! ~~E _E~~ES~~E ~2,!C!_J
/
n r..-------------------Ij
Figure 2.1 Manual Carriage Lock Location
2.3.2 Diagnostic Test
The drive should be subjected to a thorough diagnostic test and exercise as outlined in Chapter 8("Diagnostics") of this
manual, A
CRC-Format Check should be done for the drive, as well as verifying the Drive Parameters (specifically the
Spare Track Table and the Virtual Drive Offset Table).
A
new drive may beshipped with up to four tracks spared, and consideredoperational. When the Drive Parameters and
the VDO Table is first checked, these parameters should be noted, recorded on alabel, and attached to the drive. In the
event that the drive format is disturbed in shipment, it may be necessary to reformat the drive. The drive will be
reformatted with default parameters (Spare Track Table: no tracks spared. VDO Table: Drive 1=0. Interleaving Spec:
9). This will cause no problems as long as the drive has never had tracks spared. If the drive has ever had a track spared,
the Spare Track Table must be reconstructed, as well as the VDO Table (20-MB only) before the data is restored.
Knowing
what tracks must be spared will speed this procedure. Note on the label any future tracks spared.
Installation
and setup procedures are covered in the "Corvus Installation Guide" and "Corvus User Guide" for the
particular system. These aspects will not be addressed further in this document.
4

CORVUS DEALER SERVICE
2.4 Installation Considerations
All electronicequipment needs cooling and the Corvus Disk is no exception. When installing, do not "pigeon-hole" the
drive. There shouldbesufficient open air both front and rear. Place the drive on a levet hard surface without foam or
carpeting which may restrict airflow.
Be sure the proper line voltage has been selected. Referring to figure 2-2, proceed with the following instructions:
Figure 2-2. CORCOM Unit
1. Remove power cord from CORCOM unit at rear of drive.
2. Slide plastic door to the left, uncovering fuse.
3. Remove fuse.
4. Using apair of needle-nose pliers, remove voltage selection PCB from just below fuse holder.
5. Position voltage selection PCB so that proper voltage is visible when PCB is inserted.
6. Reinsert fuse, using correct value: 4A/IOO-120VAC, 2A/220-240VAC.
7. Slide plastic door to right.
8. Connect power cord to CORCOM unit, and to power outlet.
5