23 Mar
1998
23 Mar
'98
5:05 a.m.
On Mon, 23 Mar 1998, Doug Spence wrote:
I'm afraid it's not that easy. I did pull out the flashlight and take
some good close looks inside the drives tonight, though, and I think I
know how it determines the drive number now.
At the back of the main circuit board, just in front of where the ribbon
cable connects to it, there is a 14-pin chip with a label "1F" beside it.
In drive A, there is an empty 16-pin socket beside it, with "2F" written
on the circuit board beside it. Drive B has something IN this socket - a
BLUE 16-pin chip.
The BLUE chip is a terminating resistor array and should be installed in
the last drive on the ribbon cable - the B drive. Leave it there.
It is possible that the 14pin socket is the drive selector. If so, it
should not be completely empty. There might be a wire jumper or two
inserted, but what I would expect you to find is a 'chip(?)' that looks
something like this:
________________________
| |
| \/ \/ \/ \/ \/ \/ \/ |
| /\ /\ /\ /\ /\ /\ /\ |
|______________________|
New and unused, the points that I have shown would join to make a pin
to pin connection. One uses a small screwdriver or Xacto knife or such
to cut through and open the connection. For drive selection, only one or
two be making a connection.
On Sun, 22 Mar 1998, Pete Turnbull wrote:
No, that is not a problem.
I don't know much about Kaypros, but is it
possible that one of the sets of
drives is 40-track and the other is 80-track?
I don't know enough about Kaypros myself to answer this one.
Or that one set is single-sided and the other is
double-sided?
Both machines have single-sided drives. And the boot disk I'm using is
definitely single-sided, because I duplicated it using TeleDisk with side
0 only, and the copy boots up and runs WordStar just fine.
When you start up the machine and it tries to
boot, does a light come on,
on the disk drive (which would indicate that the drive is being accessed)?
Yes. The light for drive A comes on, and the motors for both drives come
on.
I get the same response out of the machine whether I use the Kaypro boot
disk or an MS-DOS disk. But it is paying enough attention that it
immediately tells me "I cannot read your diskette" when I insert a
cleaning disk. :) [which makes cleaning a bit difficult]
Also, just for the hell of it (and it's probably a Bad Thing(tm)) I nudged
the head forward when the machine was off, to see if it would move when
power was applied. And it did move back to its usual position. Anyway, the only other thing I could try is to make
drive B in the 2 think
that it's drive A, to see if I can boot from there. Does anyone know how
these drives decide which one's A and which one is B? And can I switch
their identities without removing the drives from the metal housing? I
don't have the proper screwdriver to remove the drives.
Usually there's a set of jumpers, or sometimes a small DIL switch pack, which
select one of four disk addresses. They may be labelled DS0, DS1, DS2, DS3 or
perhaps D1, D2, D3, D4. D0=A and D1=B. Just in case it was simply a matter of a missing part
in drive A of the
Kaypro 2, I inspected the Kaypro II's drives, and they were identical.
There's a blue 16-pin chip sitting in the socket of drive B, and not in
drive A. That along with the "2F" labelling seems to be pretty clear.
Now the problem is swapping that "chip" from one drive to the other. I
don't think I should even make the attempt without first getting the
drives out of the machine. Which means I need an appropriately-sized
6-sided screwdriver. :/
What you need is what is called an Allen Wrench. They come in all shapes
and sizes. Your friendly local hardware store or electronic shop should
be delighted to sell you one or a set.
- don
Doug Spence
ds_spenc(a)alcor.concordia.ca
donm(a)cts.com
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