27 Feb
2003
27 Feb
'03
1:15 a.m.
From: Patrick Finnegan <pat(a)purdueriots.com>
Aparently, the Drive 0: is bad. Replacing it with
the 1: or an IBM-branded Tandon drive from an IBM
5150 PC, it seems to try to boot from the disk. No
disk in the drive (or the disk upside down) yields a
"Diskette?" message on the display. A disk placed
right-side up, which should be bootable, gives no
messages on the display after power-up or reset.
However, with a disk inserted, the drive light (and
motor) turn> off after approx 7 seconds.
Ok..
Take a look at your "1:" drive. Near the connector you
should see a socket with something that looks kind of
like a chip in it.
But, it will have 4 metal bridges and three will be
broken. On your "0:" drive the first one will be in
place and 2 - 4 will be broken.
On the "1:" drive, the first, third and fourth should
be broken and the second bridged.
If you swap these between the two drives, you ought to
be able to turn the "1:" drive to a "0:" drive.
As for your IBM drive, it is probably jumpered for DS1
("1:" drive). If you can find the jumpers on the logic
board, move the jumper from DS1 to DS0 if you'd like
to try to use that as the "0:" drive (leaving the "1:"
drive as-is).
Let me know if that helps you.
I tried using a boot disk that I got with the
machine, and a fresh one from a .dsk file of LS-DOS
6.3.1H from Tim Mann's web site, using Tony's
trsfmt and diskdmp. The image works with xtrs too,
so I'm fairly confident that it should work when
stuck on a floppy.
Sounds ok to me...
Regards,
Al
27 Feb
27 Feb
2:03 a.m.
On Thu, 27 Feb 2003, Al Hartman wrote:
Ok..
Take a look at your "1:" drive. Near the connector you
should see a socket with something that looks kind of
like a chip in it.
But, it will have 4 metal bridges and three will be
broken. On your "0:" drive the first one will be in
place and 2 - 4 will be broken.
On the "1:" drive, the first, third and fourth should
be broken and the second bridged.
If you swap these between the two drives, you ought to
be able to turn the "1:" drive to a "0:" drive.
Umm, actually, 'no'. The cable has pins removed to change drive selects,
and the drives don't have any method of setting the drive selects. So,
swapping the position of the drives changes what drive they are. The LED
on the front of the drive confirms that.
As for your IBM drive, it is probably jumpered for
DS1
("1:" drive). If you can find the jumpers on the logic
board, move the jumper from DS1 to DS0 if you'd like
to try to use that as the "0:" drive (leaving the "1:"
drive as-is).
Now, the IBM drive has one of those annoying 'broken-jumper' IC things.
I've circumvented that with a staple for now, and it gets selected
properly.
Let me know if that helps you.
I seem to have no problem with the drive selects. I'm fairly certain that
the drives, their cable, and the disks are good. What's the next thing to
check?
Is there an easy couple line program I could type up in basic that using
INP() and OUT() to test the drive controller to see if it can read from
the disk? I _could_ read the tech manual I have, but I tend to be lazy
when it comes to re-inventing things that other people already have done.
One last thing, if it matters... it seems my machine was upgraded to 128kB
RAM. Is is possible that the machine has bad memory that shows up when
booting from a disk but not when starting up basic? I haven't tried any
'test' basic programs yet, so I'm not sure how well basic really works
either.
Pat
--
Purdue Universtiy ITAP/RCS
Information Technology at Purdue
Research Computing and Storage
http://www-rcd.cc.purdue.edu
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