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Text File
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1993-06-13
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7KB
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199 lines
Using TEAC 3.5" 720K Floppy Drives
In A Rainbow 100
March 26, 1992
INTRODUCTION
This document tells how to install a 3.5" 720K TEAC floppy disk
drive in a Rainbow.
You can install a 3.5" 720K floppy drive in the second drive bay
of the Rainbow and connect it to the unused plug (reserved for
drives C and D) of the Rainbow's floppy disk controller with a
34-pin cable.
But you'll need MS-DOS 3.10B to access it. And if you don't
already have a 3.5" I-Drive from Suitable Solutions, you won't be
able to format disks on it.
There are several parts to this puzzle: the software, the drive
itself, mounting hardware, and the cable.
SOFTWARE
There are two software drivers available to tell MS-DOS about
your drive. Both require MS-DOS version 3.10B.
IMPDRIVE.SYS is a public domain driver available on
CompuServe and from the SF Fido.
Suitable Solutions shipped their own driver with their 3.5"
I-Drive. The last version was named IDRIVE32.SYS and read
three different 720K disk formats. SS also shipped
IFORMAT.EXE with their drives, which permitted formatting
3.5 disks.
HARDWARE
The Drive
Suitable Solutions shipped TEAC 3.5" drives in their I-Drive. The
part number of this drive is 19307321-12. The model number is FD-
235F, which tells you its a 3.5" double density double-sided
floppy drive.
TEAC has since replaced model it with part number 19307331-12,
same model number.
The replacement has a far more elaborate jumper configuration
than the old model. To configure the old model, you put one
jumper on the pins marked RY and another on the pins marked D1.
The new model has a grid of pins running 1-4 on one side, and A-G
on the other.
The object of the game is to set the drive to respond as Drive 1
(not Drive 0, not Drive 3 and not Drive 4), and to make sure pin
34 is always Ready.
To do this on the new drive, you only have to change one jumper
from the default PC/AT configuration TEAC ships. Move the jumper
connecting pins B4 & C4 to A4 & B4. (See illustration below.)
G o o . . o o Represents a single jumper over two pins
F . . . . . Represents an uncovered pin
E . . . .
D . . . . This setup makes pin 34 Ready, and the drive
C . . . o respond as D1
B o o . o
A o o . .
1 2 3 4
Confirm that the drive will respond as D1 by making sure there's
a jumper connecting pins B1 & C1.
You'll see a few other jumpers, which you can leave alone. Just
for your information:
A3 & B3 HA set for 1MB mode fixed.
G3 & G4 REN set to enable auto-recalculation.
FG Short between FDD frame and DC 0V.
Should you buy a TEAC with a different jumper board, you can get
the spec sheet faxed to you from TEAC America: 213 726-0303.
Mounting Hardware
The 3.5" drive needs a 5.25" frame. TEAC kit MF-520 includes a
shorter frame than that found on the I-Drive TEAC, screws, power
cable, and a short extender board.
If you are installing just this drive, you'll need some sort of
rail.
If you are installing this piggyback on a hard drive, you'll need
to fix the 5.25 frame to the hard drive. JDR Microdevices sells
such a thing for $2.95. Or you can use your imagination.
In either case, you must be sure to cover the whole opening in
the Rainbow drive bay. If you don't, air flow over the
motherboard will be disrupted and you'll overheat chips,
shortening their life. Use a half-height bezel if you just have
the 3.5" drive. Hard disks come with their own bezel.
If you are replacing an old I-Drive, use the mounting frame from
the older drive. The shorter frame makes it hard to connect the
ribbon cable (it's deeper inside the housing and you have to
unfold the cable and give it a twist), and the bezel is a little
taller. You can certainly use the new frame, if you prefer.
The Cable
The extender board connecting old TEACs to the ribbon cable had
one jumper on it labeled ST/OP. In the ST position, pin 34's
status was available to the controller; in the OP position, pin
34 was cut off. Just turn the board over to see for yourself.
Note that the slot to orient the edge-connector correctly is on
the LED side of the drive (not the button side). That's because
the board reverses the pins.
New TEACs include an extender board, but it's much smaller, does
not include the pin 34 jumper, and does not flop the pins. The
edge-connector slot is consequently on the button side of the
drive now. If you use this extender you'll have to twist your
cable to mate correctly, contrary to anything else you may have
read.
In short, trust the slot.
The extender board is optional (at least on the new model). You
can connect the cable directly to the drive if you have a long
enough floppy cable with pin connectors (like that supplied for a
second set of RX50s) rather than an edge connector.
Otherwise, Radio Shack sells the parts you need to make the
cable: a 34-pin edge connector, a 34-pin plug (similar to the one
on the Rainbow's floppy cable), and 34-pin cable (blue with blue
and red stripes).
Make sure to connect the supplied power cable to the power cable
on the Rainbow power supply. The cable is notched so you can't
connect it incorrectly.
---------------------------------------------------------------
Rainbow disk drive to read RX50 and IBM 360k media.
===================================================
DISK DRIVE: TEAC MODEL FD-55FR 510-U (720K DS)
PIN CONNECTIONS MULTIMETER READINGS ON TRANSISTOR
--------------- ---------------------------------
PINS 12 & 32 Base
B .
. 204 199
PIN 10 . . PIN 29 . .
E C E C
TRANSISTOR IS A 2SB22 OR SIMILAR GERMANIUM , AND IS ATTATCHED TO THE DRIVE
EDGE CONNECTOR ON THE DRIVE ITSELF.
Pin numbers above refer to the floppy drive edge connector.
Connected to drives C & D socket, C: drive can be used for normal
RX50 media, and I: drive becomes the IBM format 360k drive.
I: and C: drives are the same physical unit.
(You can also double the capacity of your RX50's as well, try formating
D: drive, and you are actually using the other side of the disk in
C: drive. WARNING - you will not be able to read the second side on
a normal RX50 drive.)
Include the following command in your CONFIG.SYS file,
DEVICE=IDRIVE.SYS
This teac drive can also be used to replace the DEC RX50 units, is
faster, and quieter.
I have had one problem switching disk's between the DEC RX50, and
the TEAC diskette drive with RX50 media, and that is on the drive motor
startup, you will get a "Abort, Retry, Ignore" message, just press R for
retry, and continue. The motor in the TEAC drive does not startup within
the 500ms specified by Digital. This problem could be fixed by changing
the time out in the operating system, or in the IDRIVE.SYS device driver.
(Preferably in the OS)
Ian Manners 1990