
                                 READ THIS FIRST

                               INSTALLATION GUIDE

                                   WD1004-27X
                                   WD1004A-27X
                        Winchester Disk Controller Boards

                                  FEBRUARY 1989

                   COPYRIGHT 1989 WESTERN DIGITAL CORPORATION
                               ALL RIGHTS RESERVED

INFORMATION FURNISHED BY WESTERN DIGITAL CORPORATION IS BELIEVED TO BE 
ACCURATE. HOWEVER, NO RESPONSIBILITY IS ASSUMED BY WESTERN DIGITAL CORPORATION 
FOR ITS USE; NOR FOR ANY INFRINGEMENT OF PATENTS OR OTHER RIGHTS OF THIRD 
PARTIES WHICH MAY RESULT FROM ITS USE. NO LICENSE IS GRANTED BY IMPLICATION OR 
OTHERWISE UNDER ANY PATENT OR PATENT RIGHTS OF WESTERN DIGITAL CORPORATION. 
WESTERN DIGITAL CORPORATION RESERVES THE RIGHT TO CHANGE SPECIFICATIONS AT ANY 
TIME WITHOUT NOTICE.

Radio Frequency Interference Statement

This Western Digital product has been verified to comply with the limits for a 
Class B computing device pursuant to subpart J of Part 15 of FCC rules. This 
does not guarantee that interference will not occur in individual 
installations. Western Digital is not responsible for any television, radio, or 
other interference caused by unauthorized modifications of this product.

If interference problems do occur, please consult the system equipment owner's 
manual for suggestions. Some of these suggestions include relocation of the 
computer system away from the television or radio or placing the computer AC 
power connection on a different circuit or outlet.

This digital apparatus does not exceed the Class B limits for radio noise for 
digital apparatus set out in the Radio Interference Regulations of the Canadian 
Department of Communications.

If you require further information or other technical support, please contact 
your authorized dealer:

**************************************************************************
INTRODUCTION
**************************************************************************

The WD1004-27X and WD1004A-27X boards are easy to install. The following 
is a summary of the installation steps.

1. Preliminary: set jumpers, drive configuration
2. Install hardware: drive, board, connect cables
3. Install software: use debug, low level format, etc.
4. Check installation: start system, use new board & drive













                                     CAUTION

     Handle the controller board by the ends of the board. Some of the chips 
     are static sensitive and damage may occur if the board is incorrectly 
     handled.
     
**************************************************************************
ABOUT THIS GUIDE
**************************************************************************

Angle brackets < > refer to a key. Therefore the symbol <Enter> refers to the  
Enter key.

This guide was written using the IBM* XT computer as a model. Sometimes 
specific examples, such as errors, refer to the IBM error code numbers. 
Therefore if you have an XT compatible computer, your error numbers may be 
different.

About Menu Screens:

Because computer manufacturers are always updating their products, and this 
installation guide covers installing both WD1004-27X and WD1004A-27X controller 
boards in many XT compatible computers, some of the menu screens may not be 
exactly the same on your system. Always follow the instructions on your 
computer screen.

* IBM is a registered trademark of International Business Machines Corporation.


                                        1

                             SOME PRELIMINARY STEPS

Before you begin the actual installation of the hardware and software, 
there are some preliminary steps that you need to do.

**************************************************************************
GATHER SUPPLIES
**************************************************************************

The installation requires that you gather the following tools and supplies.

  -  screwdriver

  -  XT compatible computer with space to hold the internal drive

  -  RLL hard disk drive(s)<187>with ST506 interface

  -  interface cables (20-pin data cables & 34-pin control cable)

  -  DOS version 2.0 or later (DOS 3.1 or later recommended)

  -  installation manual for XT compatible computer

  -  installation manual for hard disk drive












**************************************************************************
IDENTIFY DRIVE
**************************************************************************

The WD1004-27X and WD1004A-27X boards work with any hard disk drive that has 
the ST506/412 drive interface and no more than 1024 cylinders and 16 heads. The 
Seagate 238 hard disk drive unit is such a drive.

Look in your drive manual to verify that you have an ST506/412 RLL drive or 
check with your dealer.

Then check the drive manual for the drive parameters, such as those listed in 
Table 1-1. You'll need this information to select the proper low level format.

Table 1-1. WD1004 and WD1004A Default Drive Parameters

Formatted Capacity   Number of Heads   Number of Cylinders   Sectors per Track

   32MB                     4                615                   26


This board works with RLL drives. If you have an MFM drive you should use the 
WDXT-GEN2 or WD1004A-WX1 board. 

**************************************************************************
IDENTIFY BOARD
**************************************************************************

This document describes the installation of the two controller boards, WD1004-
27X and WD1004A-27X. These controllers are similar functionally, except for a 
few features. These boards are described below.

WD1004-27X Board

Figure 1-1 shows the connector locations (J1, J2, J3, J4, and J5) on the WD1004-
27X board and the location of the jumpers (W17 to W22, R23, and W25 to W28).

The WD1004-27X board has a connector at J4, which allows the controller to 
connect power to FileCard drives and jumpers W17 to W22, which permit selection 
of additional options.  Also the WD1004-27X board can be used as a secondary 
controller.

WD1004A-27X Board

Figure 1-2 shows the connector locations (J1, J2, J3, and J5) on the WD1004A-
27X board and the location of the jumpers (R23, and W25 to W28).  The WD1004A-
27X board cannot be used as a secondary controller.


















Figure 1-1. WD1004-27X Connector and Jumper Locations
                                                                     Ŀ
                                                                          
   ĳ  o  
    o            J2Ŀ          J1Ŀ              ĳ
      J5Ŀ                    Ŀ     
          J3Ŀ                                  W17        
                           ĿĿ     W18        
      ĿĿ             Ŀ                         W19        
                                                   W20        
                                                   W21        
                                                   W22        
                                                
         Ŀ                                           R23        
                                          R24        
                           Ŀ                                
                                                         Ŀ    
                                                          W25       
                                                     W26       
                               Ŀ   W27       
                                            External ROM    W28       
                                            Socket             
                                                           
                 J4                                 Ŀ         
    o                                                   o  
   Ŀ                                       
                   

Figure 1-2. WD1004A-27X Connector and Jumper Locations
                                                                     Ŀ
                                                                          
   ĳ  o  
    o            J2Ŀ          J1Ŀ              ĳ
      J5Ŀ                                  
          J3Ŀ                                               
                           ĿĿ                  
      ĿĿ             Ŀ                                      
                                                                
                                                                
                                                                
                                                         
         Ŀ                                           R23        
                                          R24        
                           Ŀ                                
                                                         Ŀ    
                                                          W25       
                                                     W26       
                               Ŀ   W27       
                                            External ROM    W28       
                                            Socket             
                                                           
                                                      Ŀ         
    o                                                       o  
   Ŀ                                       
                   











BIOS ROM Incompatibility

BIOS is an acronym for Basic Input Output System. ROM is an acronym for Read 
Only Memory. The BIOS ROM is a program on a computer chip that tells your 
computer how to operate devices attached to your computer.

Some XT compatible computers do not operate with the Western Digital BIOS ROM 
because of an incompatibility. Most of these computers are listed in Appendix 
A. Check Table A-1 to see if you have one of these computers.

If this is the case, you need to disable the Western Digital BIOS ROM by 
setting a jumper resistor.  If you have one of these computers, omit the low 
level format in this guide and instead follow your computer manufacturer's 
software installation instructions for low level formatting.

**************************************************************************
JUMPERS
**************************************************************************

A jumper allows you to change certain functions on your controller board. 
Western Digital set the jumpers for the most common applications. It is 
unlikely that you will need to change any of the jumper settings.

Appendix B contains a complete explanation of jumpers.

                                     CAUTION

           Handle the controller board by the ends of the board. Some of the 
           chips are static sensitive and damage may occur if the board is 
           incorrectly handled.
            

Do I Need To Change Any Jumpers?

No. Do NOT change any jumpers on your new WD1004 or WD1004A controller boards, 
unless you have one of the following conditions:

  -  The new board is your second hard disk controller in the 
     system.

  -  You have another peripheral unit which uses interrupt signal 
     IRQ5.

  -  You have a BIOS ROM which is incompatible with your new 
     controller.

  -  You have a hard disk drive whose parameters are different 
     from those listed in Table 1-1. This requires you to do the dynamic 
     configuration.

Change Jumpers

When you have one of the special conditions listed above, you need to add a 
jumper. In all other cases, do NOT add a jumper.












  -  If the WD1004-27X board is the second controller, change 
     the controller address at W21 & W22. Check the first controller 
     manufacturer's manual for the addresses and also see Appendix B.

  -  If another peripheral uses IRQ5, add a jumper at W27.

  -  If the computer motherboard BIOS ROM is incompatible, add 
     a jumper resistor at R23.

  -  If you plan to do a dynamic configuration, remove the jumper 
     at W25 and place it at W26.

See Appendix B for information on changing jumpers.

**************************************************************************
SET HARD DISK DRIVE CONFIGURATION
**************************************************************************

This section "Set Hard Disk Drive Configuration" refers to procedures that you 
do to your hard disk drives and not to your WD1004 or WD1004A controller. Since 
the WD1004 and WD1004A boards work with many hard disk drives, you need to 
consult your drive manufacturer's manual for exact details.

You need to set the configuration for your hard disk drive unit, before you 
install the unit into your computer. You set your hard disk configuration by 
adjusting jumpers, switches, or termination resistors on the hard disk unit.

Drive Settings

The two settings that you can change are:

  -  drive number

  -  drive termination resistor

You frequently don't have to modify the factory settings. The exact number of 
settings that you change depends on your disk drive and computer.

Control Cables (34-pin Connectors)

Setting the drive number depends on the type of control cable that connects 
your drive to your controller board. The two types of cables are listed below.

  -  without a twisted section

  -  with a twisted section

Do NOT use cables from floppy drives. Hard disk cables are different!

First identify which cable you are going to use. Look at the control cable and 
determine whether it is twisted. The control cable has the 34-pin connectors.















If you already have one hard disk attached to your WD1004 or WD1004A board and 
you plan to use the existing cable in your computer, you may have to open the 
computer case. See your computer manufacturer's instructions.

Set Drive Number

When the 34-pin control cable has a twisted section, set the jumpers or 
switches on both drives for drive select 2. See Figure 1-3.


     ڿ               ڿ    ڿ      ڿ               ڿ    ڿ
     ĳĳ      ĳĳ
     ĳĳ      ĳĳ
     ĳĳ      ĳĳ
     ĳĳ      ĳXXĳ
     ĳĳ      ĳXXĳ
                                                 
       Non-twist Cable                  Twisted Cable

Figire 1-3. Cables with and without a twisted section


When the 34-pin control cable has NO twisted section, set a jumper or switch on 
the first drive for drive select 1 and the second drive for drive select 2.

See the drive manufacturer's manual for detailed instructions on how to set the 
drive number.

Set Drive Termination Resistor

The drive termination resistor should only be on the drive, which is the last 
physical drive installed in a daisy chain configuration. When you have two hard 
disk drives, remove or disable the termination resistor from the drive, which 
you plan to attach to the middle connector .

If you have only one fixed hard disk drive, do NOT change the termination 
resistor. Drives are usually set at the factory as the first hard disk drive 
(i.e., to be the only drive in the system).

See the drive manufacturer's manual for detailed instructions on how to remove 
or disable the termination resistor.

Note: A daisy chain cable has three connectors. The electrical signal in a 
daisy chain configuration moves from one connector to the next in sequence.

**************************************************************************
CHECK COMPUTER
(Incompatible System BIOS ROM)
**************************************************************************

Some early versions of XT type computers have system BIOS ROMs that are 
incompatible with your WD1004-27X or WD1004A-27X controller. Follow the 
instructions in the next section "Read System BIOS ROM Date" to determine if 
you have one of these systems.













Read System BIOS ROM Date

DEBUG is a program which allows you to look at information in your computer on 
a fundamental level. You can enter the Debug program and use it to read a 
portion of your computer's ROM (read only memory). By following the steps 
below, you can determine the date the system BIOS ROM was created for your 
computer.

The Debug program should be supplied on your DOS diskette. See your DOS system 
manual for complete instructions on how to use the Debug program.

Place the diskette containing the Debug program in drive A, then

1.   At the prompt (A>),

     Type: DEBUG
     Press <Enter>

2.   At the debug prompt (-),

     Type: d f000:fff5 fffc
     Press <Enter>

3.   Date returned is (10/27/82) OR LATER

4.   To exit debug,

     Type: q
     Press <Enter>


                                        2

                          HOW TO INSTALL YOUR HARDWARE

This section tells you how to install the hardware portion of your WD1004-27X 
or WD1004A-27X controller board. You will install the controller board in an XT-
compatible expansion slot.

Do not attempt to install your hardware unless you have set the hard disk drive 
configuration as explained on page 1-9 and set the WD1004 or WD1004A board 
jumpers, if required.

The installation requires you to remove the cover from your computer. See your 
PC manual for exact instructions on how to remove the cover.

@BODY TEXT PBA = If you are replacing an existing controller, then you also 
have to remove your old hard disk controller.

If you want two hard disks on one controller, use a daisy chain cable to 
connect them onto one controller board. A daisy chain cable has 3 connectors.

1.   Turn your computer power switch to OFF and unplug power cord.












2.   Use a screwdriver to loosen the cover screws. Then remove the computer 
     cover, so that you can see the expansion slots.

3.   Place your hard disk drive unit(s) into the computer case 
     and mount per the manufacturer's installation instructions.

4.   Look and see which expansion slots are empty. Use an empty slot that has 
     the same type of edge connectors as the WD1004 or WD1004A 
     board, except as noted below.

     Note: For IBM XT owners: DO NOT use the slot closest 
     to the power supply. Use an expansion slot at least one position removed 
     from the power supply.

     You may have to leave the fastening screws loosely connected, so that you 
     can attach the cables.

     Or if you are removing a controller, locate the one which has the old 
     controller in it. Use this expansion slot.

     Note: You can also install a new fixed hard disk drive on an existing 
     WD1004 or 1004A controller. See Appendix A.

5A.  If you are removing an old controller, loosen the screw which holds the 
     old controller board in place. Then slide the old board out of the 
     expansion slot and remove the cables. Locate the old rear slot cover and 
     place it on your computer case. (You probably removed this old slot cover 
     when you installed your old controller board.)

5B.  If you are using a "new" expansion slot, remove the screw, but keep the 
     rear slot cover in place. Save the screw to hold the new controller board.

6.   Connect 34-pin wide control cable to your WD1004 or WD1004A board. Follow 
     steps A or B. These instructions are for both one or two drives on the 
     same controller.

A.   (for 1 drive only) Connect the 34-pin (wide control cable) 
     connector to J1 on the controller board. Attach Pin 1 of the cable 
     connector to Pin 1 on the controller board. See Figure 1-1 or Figure 
     1-2.

     Pin 1 of the cable connector is marked and is on the color coded edge of
     the cable. Do NOT force the cables and connectors.

B.   (for 2 drives only) If you are installing two hard disk 
     drives on one controller, use a daisy chain cable. A daisy chain cable 
     has 3 connectors.

     Connect the 34-pin wide connector on the longer daisy chain 
     cable section to J1 on the WD1004 or WD1004A board. See Figure 1-1 
     or Figure 1-2 and Figure 2-1.

7.   Connect 34-pin wide control cable to drive unit.













                Ŀ
                 FIRST DRIVE   Ŀ   34 Pin Connector
                Ŀ
                                   
                                     (Shortest Cable)
                Ŀ  
                 SECOND DRIVE  ٳ   34 Pin Connector
                Ŀ
         (Termination Resistor     
              Removed)               (Longest Cable)
                                   
                                   
                                   
                     ٳ
                      
            ĳĳĿ  34 Pin Connector
                      J1  
            Ŀ        
               
             WD1004-27X or
             WD1005A-27X

                   Figure 2-1.  Daisy Chain Cable Connections

A.   (for 1 drive only) Connect the free end of the 34-pin control 
     cable to the hard disk drive.

B.   (for 2 drives only) Connect the end 34-pin connector on 
     the shorter daisy chain cable section to the first hard disk drive 
     unit's 34-pin connector. See Figure 2-1.

C.   (for 2 drives only) Connect the middle 34-pin connector 
     on the shorter daisy chain cable section to the second hard disk drive 
     unit's 34-pin connector.

Remember: The second hard disk drive unit is the unit from which you removed or 
disabled the termination resistor and changed the drive number. See page 1-12.

8.   Connect 20-pin data cable(s) to the drive unit(s) 20-pin 
     connectors. Attach one 20-pin data cable to the first hard disk drive 
     unit. If you are installing a second drive connect the second 20-pin 
     data cable to the second hard disk drive unit.

9.   Connect 20-pin data cable(s) to the WD1004 or WD1004A 
     board as described below.

A.   Connect the 20-pin data cable from the first drive to J2 
     on the controller board. Attach Pin 1 on the cable to Pin 1 on the 
     controller board. See Figure 1-1 or Figure 1-2.

B.   (for 2 drives only) If you install a second hard disk drive, 
     connect the second 20-pin data cable from the second drive to J3 on 
     the controller board. See Figure 1-1 or Figure 1-2.













10.  (optional for systems with LED cables & J5 connectors) Connect 
     the 4-pin external LED cable connector to J5 on the controller board. 
     This instruction only applies to WD1004-27X controllers.

11.  Connect power from your computer's internal power supply 
     to the drive. Follow instructions for either A or B.

A.   Locate the internal 4-pin power connector(s) on your computer. 
     See your computer manual. Connect this internal 4-pin 
     power connector to your fixed hard disk drive unit's power connector 
     plug.

B.   (for 2 drives only) If you are installing 2 drives, you 
     need either two internal power connectors on your computer or you 
     need a "y" adapter, which splits the power cable. See the manufacturer's 
     manual.

     Connect the second drive unit to the second power connector 
     plug or to the "y" adapter.

12.  Install the controller board into the expansion slot that 
     you selected in step 4. The WD1004 or WD1004A's edge connectors (shown 
     in Figure 1-1 or Figure 1-2) fit firmly into the computer's motherboard. 
     See your computer manual for the location of your computer's motherboard. 
     Press firmly on the WD1004 or WD1004A board as you insert it into 
     the expansion slot. Check that the board is seated properly by pressing 
     down firmly on both ends of the board. 

13.  After the board is seated firmly in the expansion slot 
     socket, secure the board using the clip that is on the end of your 
     board. Place the bracket screw (which you removed in step 5) over 
     the clip and rear slot cover. Then screw the clip and slot cover to 
     the computer chassis.

                                     CAUTION

           When routing cables, be careful not to pinch them. 
           Cables must not get caught between the cover and the boards nor 
           should they obstruct any air flow path from fans or vents.
            

14.  Place extra cable lengths so that they are out of the way.

15.  Replace the computer cover. Then plug the power cord back 
     into your computer.

Your hardware controller installation is complete. However, your WD1004 or 
WD1004A controller board is really a complex circuit composed of both hardware 
and software, so that while the hardware installation is complete, you still 
need to install the software. Proceed to the next section for the software 
installation steps.

Tighten hard disk unit(s) to computer case, etc. if not already done so in step 
3.