ADDITIONAL/REPLACEMENT HARD DISKS
for
CP/M Kaypros with TurboROM
The Advent TurboROM allows any CP/M Kaypro (except Robie) to use up to
two Hard Disks of up to 56 Mb (formatted) each. Adding a hard disk is
not difficult and does not require a great deal of technical knowledge.
It does require care and reasonable manual dexterity. Some situations
require the use of tools other than simple screw drivers and these will
be outlined later.
The components required to interface a hard disk are as follows:
a) Host Adaptor or Clock. This special circuit board plugs into
the Z-80 socket on the main circuit board and provides a 40 pin
connector to which a Western Digital WD-1002-HDO (or -05) hard disk
controller can be connected. A Kaypro 10 has the interface for the
WD-1002-HDO built-in and the host adaptor is not needed unless an
Advent RAM disk is also being used.
b) A hard disk controller. The only controllers supported by
the TurboROM is the WD-1002-HDO (and the WD-1002-05 which is the same
controller with a floppy controller also on the board). A Kaypro 10
already has this controller mounted on the side of the floppy disk
housing.
c) Hard Disk(s). Any drive which supports the Seagate 506
interface can be used. (In fact some drives with Seagate 412
interface can be used but you should know what you are doing before
you embark on this.)
d) Power Cables. The Hard disk controller requires 5 volts at
about 1.4 amps. The Hard disk requires 5 volts and 12 volts, the
actual power required depends on the drive chosen. The standard
method of providing power for an internal installation is to use 'Y'
cables which are plugged into an existing disk power outlet and
provide one additional outlet.
e) Signal cables. The WD Controller is connected to the host
adapter via a 40 conductor cable with a socket on each end (it may
have up to two additional sockets for RAM disks). It is recommended
that this cable be limited to 3 feet or less. Each hard disk is
connected to the controller via a 20 conductor radial cable. The
controller has a plug for each radial cable. All hard disks are
connected to a main daisy chained 34 conductor select cable. Both
the radial and select cables can, if correctly terminated, be
extended for a considerable distance (up to 15 feet) without any
problem.
RECOMMENDED HARD DRIVES
Many drives will work. However, if you are purchasing a new drive
you should look for the following features.
a) Low Power. This is particularly important if you are
considering mounting the drive internally. A Kaypro 10 can usually
support up to two half high drives or one modern full high drive. Some
older full high drives are beyond the capabilities of the power supply
(and cooling fan).
b) Quiet operation.
c) The number of heads is preferably 2, 4, or 8 rather than 3, 5,
6, or 7. This improves performance. Other things being equal, a 20 Mb
drive of 8 heads and 306 cylinders will perform better than a 20 MB
drive of 4 heads and 612 cylinders. However, for characteristic (a)
above the Seagate ST225 is still a desirable drive as half high 8 head
drives are rare or non-existent.
Plu*Perfect Systems supplies the following drive types:
1) Rodime RO252. This is an 11 Mb half height drive. Actually it
is a 3.5 inch drive that has been mounted in a 5.25 inch frame and
incorporates liberal shock mounting. It is also low power, quiet and
reliable.
2) Seagate ST225. This is a 22 Mb half height drive. It is also
low power, quiet and reliable. It does not have special shock mounting
but does have specifications similar to the Rodime ( 40G non-operational
and 10G operational). This drive is excellent for adding (or replacing)
a Kaypro 10 drive, external mounting on any machine and for a Kaypro
II/4 that is NOT portable it can be mounted internally.
Many other drives have been used successfully, including Ampex, big
Rodime, Atasi, Shugart SA604, SA712 etc, though most of these have been
in external enclosures. In some cases it has been necessary to replace
the Kaypro power supply when drives are internally mounted.
We specifically do not recommend MicroScience drives. These will work
with the 84 TurboROMs (which supports both 512 and 1024 byte per sector
formats) but will have less capacity than other similar drives. These
drives cannot be reliably formatted to 1024 byte sectors and are thus
not supported by the 83 Roms (which only supports a 1024 bytes/sector
format).
CONNECTING THE DRIVE
Hard drives are similar to floppy drives in that they have to be
configured for the application. The two options the user must set are:
a) Terminating Resistor - only one of the two drives can have a resistor
installed. You should consult the drive manual for the location of this
option. If you are adding a drive to a Kaypro 10 the present drive will
already have a resistor pack installed. All drives purchased from
Plu*Perfect Systems have the terminating resistors installed, these must
be removed if the drive is to be used in multiple drive system.
Note that the drive manufacturers all recommend that the drive with the
termination resistor should be that which is electrically most distant
from the controller. With internal mounting in a Kaypro this is not a
problem, but if long cables are being usd from the drive to the
controller this must be done correctly.
b) Drive Select Jumper - each drive must be set to select at a different
address. On the TurboROM, the drives must be configured as either drive
1 or 2. (Note that drive manufacturers are not consistent about how
they number their select options. Some use DS0, DS1, DS2, and DS3, and
others DS1, DS2, DS3, and DS4 -- our terminology refers to 0, 1, 2, and
3.) All drives purchased from Plu*Perfect Systems with a Hard Disk
Controller are formatted using that controller before being shipped, so
they are set up correctly for use in a single drive system. The Rodime
drives which are purchased without a controller are shipped with DS0
selected and must be changed before use. The Seagate drive without a
controller has all 4 select jumpers installed, 3 of these must be
removed before use (see manual excerpts included with the drive).
Note that MicroScience drives used in many Kaypro 10's use a DIP switch
for both select and termination. However, there are two variants and
you should have reliable data before modifying the switch settings.
c) Power Connection - Hard disk drives require both 5 and 12 volts.
This is connected via a 3 or 4 wire cable which has a white nylon plug.
This plug is keyed so it cannot be inserted incorrectly into the drive.
Where the power is being derived from the Kaypro we usually use 'Y'
connectors to expand the number of available outlets. Be especially
careful on a Kaypro 10 because the power connector to the hard disk
controller only provides 5 volts and cannot be used as a source of power
for a drive. (It is useful for RAM disk power however.) On 84 machines,
the same wiring harness was used as on the Kaypro 10 and thus there is
often this spare 5 volt only connector available which can be used to
power your controller.
d) Select Cable - All hard drives are connected in parallel to the
controller via a 34 conductor cable. On the drive end the card edge
(connector) is usually slotted near the end nearest pin 1. You
generally will need to examine the legend silk screened on the circuit
board to determine which side has the odd numbered pins. Pin 1 on the
cable is usually marked with some identifying mark and is on the edge
with the cable stripe. At the controller end pin one of the 34 pin plug
is clearly marked with either a '1' or '^'.
e) Radial Cable - Each hard drive is connected to the controller via its
own 20 conductor radial cable. The pin and cable markings are the same
as outlined above for the select cable. Physical drive 1 (DS1) should
connect to J2 of the controller and physical drive 2 (DS2) should
connect to J3 of the controller. On modern versions of the WD 1002 this
is no problem. On older revisions there is often a problem (on some
boards the plugs were J1 J2 J3 and on others J3 J2 J1) with physically
getting the radial cable connector over plug J3. Western Digital had a
layout error which had placed plug J3 too close to the power connector.
To resolve this requires some patience and care. We have found that a
stiff backed razor blade (be very careful) can be used to remove much of
the power connector plastic housing, then gently use a file to remove as
much of the material from the connector on the radial cable without
destroying its mechanical integrity.
MOUNTING THE DRIVE
A. Kaypro 10
The Kaypro 10 is in principal the simplest installation. However, if
you are adding a second half height drive internally you must completely
disassemble the disk drive enclosure/shock mount and drill mounting
holes for the second drive. In some cases it may be advisable to drill
new holes for the original drive. When jumpering the drive selects you
should always make the drive that is slowest to start in position 1 or
the TurboROM may not sense its presence.
It is a good idea if adding a second drive, to make some provision for
displaying the "select" light. Some people have simply drilled another
hole in the front panel for and appropriate bezel. Others have gone to
some trouble to obtain a red/green LED for mounting in the existing
hole.
B. Kaypro II/2 and 4 '83
These machines have a disk enclosure which is large enough for 2 full
height or 4 half height drives. These machines also have marginal
power supplies. If you are adding an internal hard drive you may be
faced with replacing the power supply, this is hard to predict in
advance due to the great variability in the supplies used by Kaypro.
For example, we are currently running a 2 '83 with (2) Mitsibushi 96 tpi
floppies, (1) Shugart 48 tpi floppy, (1) Rodime RO252 hard disk, 1 Mb of
RAM disk. This is however getting very near the limits of this
individual power supply and we will probably replace it in the near
future just to be conservative. We have also run an ST 225 hard disk
and a standard Tandon floppy drive in another 2 '83 with no signs of
power supply distress. On the other hand a 4'83 we converted suffered
power supply overload with a single Tandon floppy and Rodime hard disk.
Physically mounting either a Rodime or a Seagate in these machines is
simple. We recommend mounting in the bottom position where no holes
require drilling and some air flow is available from the bottom slots.
Both the Rodime and Seagate use #6 screws for mounting, be careful of
using long screws that either bottom out in the Rodime or interfere with
the case on the Seagate. Do not permanently mount the drive if you are
going to use a blanking plate to fill the panel hole above the drive.
If you are using a half height blanking plate to fill the space above
these drives, the recommended mounting procedure is as follows.
1/ With the drive temporarily in position slide the blanking plate into
position above it.
2/ The securing latches on the side will prevent it from completely
going into position. Use a marker to mark on the inside of the drive
housing the position of these latches.
3/ Now dismount all drives and remove the drive enclosure.
4/ Using a small file, notch the front of the enclosure in a position
corresponding to these latches. Make the notches deep enough to clear
the back of the latches.
5/ Reassemble the drive enclosure.
6/ Mount the hard drive permanently. It is a good idea to connect the
cables to the drive at this point when the rest of the enclosure is
empty.
7/ Slip the blanking plate into position. It has to be bent gently in
the middle so that the side latches can get past the front panel. When
the bend is released it will snap securely into position.
8/ Now mount the floppy drive(s).
C Kaypro 2 and 4 '84
These machines have half height floppy drive cutouts and the same power
supply as a Kaypro 10. When mounting a hard drive in these machines the
simplest is to replace the bottom floppy drive. However, if you wish to
retain two floppy drives some mechanical work is required.
1/ Replacing a floppy.
If you are replacing a floppy with a ST225 then it is slipped in from
the front exactly as a floppy drive would be. The RO 252 is more
complicated due to the depth of the drive. The Rodime face plate should
be remove by undoing the two Allen headed screws. The drive can then be
slipped in from the rear (it is a good idea to attach the power and
signal cables to the drive before this is done). Now slip the drive
forward so that the face plate mounting holes stick out through the
front panel. Reattach the face plate and then slip the drive back and
secure it in the normal manner.
If you remove the old 'B' drive remember to move the terminating
resistor pack up to the A drive. If you are not going to use the Advent
Personality decoder it is a good idea to jumper the remaining drive as
both DS0 and DS1 so that the two drives that appear to be present to the
ROM actually can be addressed. This will save some aggravation when
using TURBOCPY, though remember that you really only have one floppy and
cannot use the copy option.
2/ Adding a Hard Drive.
You can either cutout the metal part of the panel between the two drives
and slip the drive in from the front or blind mount the drive without a
face plate behind the front panel. Blind mounting is much more
difficult as the space between the floppy drives is very tight.
Do not attempt the metalwork required to cut out the front panel unless
you are a reasonably competent craftsman or you will cosmetically scar
your Kaypro for life.
1/ Remove both floppy drives.
2/ Carefully remove the sheet metal between the drive holes using a fine
hacksaw. Cut on the interior of final opening so that the hole can be
trimmed up with a file later.
3/ Now position both floppy drives to the top of the opening and mark
the holes needed to mount the bottom floppy drive in this position.
4/ Check that the existing mounting holes in the bottom position are in
the appropriate position for mounting the hard drive. If not mark any
corrections needed.
5/ Remove the complete drive enclosure to drill the holes. Make them
slightly oversize so that fine adjustment of drive position is possible.
6/ Reassemble the enclosure and now mount the hard drive in the bottom
position. As above it is a good idea to connect its cables before
mounting the floppy drives.
7/ Now mount the floppy drives. Beware of some brands of drive that can
interfere with adjacent drive when the locking handle is in some
positions. Double check that there is no interference between the any of
the drives.