            Add a Hard Disk to a Kaypro "84" Floppy Computer


The recent computer slump has resulted in massive parts dumping on the
part of the computer manufactures to the surplus market.  I am sure that
you have seen all the ads in the papers hawking IBM ten megabyte drives
for less than $500.  Let me tell you how you can add a hard disk to your
computer.

All of the "84" series computers come with the larger power supply and
the necessary power wiring for two drives and the hard disk controller.
To convert to a K10 simply involves unplugging the lower drive, adding
the controller and host interface boards, and plugging in some new
cables.

The following is a list of the needed parts:

The hard disk itself
    Shugart 712
    Seagate 224

The hard disk controller
    Western Digital 1002-HDO or 1002-05

    Kaypro Host Interface 81-212A ( must be "A")

System ROM
    Kaypro 81-302C
    Advent 84 Turborom

Software
    Kaypro K10 F, G, or H System disk
    Advent Turborom software is supplied with its ROM

Interconnect cables
    Dual 50 pin IDC ribbon cable (computer to host)
    Dual 40 pin IDC ribbon cable (host to controller)
    34 pin IDC to 34 pin edge ribbon (controller to disk)
    20 pin IDC to 20 pin edge ribbon (controller to disk)

Hardware
    8 4-40 1/2 in spacers
    4 4-40 1/4 in flat head screws
    12 4-40 1/4 1n binder head screws
    8 #4 nylon or fiber washers

The hard disk is available from many sources.  In the December Byte
Advanced Computer Products is selling the Shugart for $229 with a one
year warranty.

The Western Digital controller is also a standard part.  Its list is
$295.  Xerox surplus outlet has them for $75 as is (the five I have
purchased have all worked), S100 is supposed to have them new for $200,
and ERAC has them used with warranty for $200.

The host interface card is a Kaypro part.  Your Kaypro dealer can order
it for you for around $30 or you can get it from ERAC for $5.

The cables are all standard parts.  Most of the connectors cost 5 to 6
dollars each and 50 conductor ribbon cable is about a buck a foot.  ERAC
has the stock kaypro cables for around $3 each, but they are too short.
You can reuse most of the connectors if you are careful and use them to
help build up to ERAC's $25 minimum order.  Their ad states that they
have 81 series ROMs, so they might have the 81-302c in stock.

Now for the construction.  I despise overly detailed instructions, so I
am only going to describe the work in general.  If you need more
specific hand holding, most user groups have at least one technical type
that can help.

Remove the main board, the floppies, and the floppy cage.

Mount the host interface card on four spacers on the floor of the
computer in the area normally covered by the cage.  Mount it with the 50
pin connector facing the rear.

Mount the controller card on the left side of cage.  Be sure to mount it
low enough to miss hitting the main board.  I only used three spacers as
the lower front one would be a real bitch to get a screw into.
Countersink the holes and use the flathead screws so that they don't
interfere with the drives.

Temporarily set the cage back in place and make up the host cables.  The
forty pin connector goes to the forty pin connector on the controller.
The fifty pin connector goes to the fifty pin connector on the main
board next to the 34 pin floppy connector.  Leave enough slack in the
cables so that they can be adjusted to not block the air flow from the
fan.

Remove the controller and mount the cage.  Mount the hard disk on the
bottom and the floppy on the top.  Both drives should have terminators
and be strapped for the lowest drive number, on some drives that is 0
and on some it is 1.

Mount the controller card using the insulators so that none of the foil
tracks on the top or bottom are shorted.

Make up the drive cables.  The 34 pin cable goes to the 34 pin connector
on the controller next to the power plug.  The 20 pin cable goes to the
center of the three clustered 20 pin connectors J2.

Remount the main board and plug in all of its cables.  Plug in all the
power cables.  The controller gets the one with only a white and black
wire.  Plug the floppy cable back in using either of the edge
connectors.

Change the ROM.  If you are using the Kaypro ROM it will be shorter and
goes all the way to the rear of the socket.

The rest of this assumes that you are using the stock Kaypro ROM and
software.  For the Advent Turborom refer to its instructions.  To use
the Turborom, you must purchase their Hard Disk Formatter also.

Power up the computer with the system disk in the floppy.  It should
come up with Kaypro 10 1.9E message and then boot from the floppy
normally.

After at least warming up for half an hour we can now format the hard
disk.  Run Format and tell it that your drive is 1,1 head 0,3 cylinders
0,305.  It takes about 45 minutes.

Now run Findbad B: and Findbad C: to lock out any bad blocks.  Run
Putsys and Putovl to write the system to the hard disk and you are done.
Open the floppy door, push reset and it should boot from the hard disk.

One of the nice things about Kaypro is the extensive public domain
support.  John Smith has supplied a turnkey ZCPR3 system that will run
on your new machine by simply running a new set of put files.  Most
kaypro user groups have it and it is on the major boards.  I recommend
it highly.  It would be a hardship to go back to the stock CP/M system.
It makes a hard disk even nicer.

I have modified several machines with no problems.  Since the entire job
involves only board swapping, with a little care you should have none
either.

Glenn Drayer
15200 Magnolia #19
Westminster, Ca 92683

...ONKUG, Newsdiskette to Kaypro Users Groups, Volume 2, Number 2.
