[comp.sys.ibm.pc.hardware] Problems with a 360K drive in an AT clone

mju@mudos.ann-arbor.mi.us (Marc Unangst) (06/05/91)

I have a no-name AT clone (the only identifying mark on the
motherboard is a silkscreened "SAM-II/10"; it's a 286/10) with an AMI
BIOS in it.  I'm trying to install a 360K drive as drive B:.  As I
understand it, the BIOS is supposed to auto-sense a 360K drive when
you go through setup, and only ask you what kind of drive it is if
it's a 1.2MB or 3.5" drive.  However, when I go through setup, it pops
up the "drive type" question for both A: and B:.  360K is not an
option; I can only choose 1.2MB, 720K, or 1.44MB.  I've tried putting
a formatted, bootable 360K disk into the drive before I boot up, but
that didn't help the BIOS recognize the drive.  The drive select
jumper is set to "1", and the drive appears to spin up fine when the
system boots.  The drive should work, since it was working perfectly
when it was in the XT clone that I salvaged it from.

Having a 360K drive isn't that important to me, but I got it for free,
and it *would* be nice to have a second floppy drive.  Any
suggestions?

--
Marc Unangst               |
mju@mudos.ann-arbor.mi.us  | "Bus error: passengers dumped"
...!hela!mudos!mju         | 

n65j@vax5.cit.cornell.edu (06/07/91)

In article <3Js233w164w@mudos.ann-arbor.mi.us>,
mju@mudos.ann-arbor.mi.us (Marc Unangst) writes: 
> I have a no-name AT clone (the only identifying mark on the
> motherboard is a silkscreened "SAM-II/10"; it's a 286/10) with an AMI
> BIOS in it.  I'm trying to install a 360K drive as drive B:.  As I
> understand it, the BIOS is supposed to auto-sense a 360K drive when
> you go through setup, and only ask you what kind of drive it is if
> it's a 1.2MB or 3.5" drive.  However, when I go through setup, it pops
> up the "drive type" question for both A: and B:.  360K is not an
> option; I can only choose 1.2MB, 720K, or 1.44MB.

Marc, you don't say whether the drive is accessible after boot.  If it is,
perhaps after you set the CMOS type to a "wrong" choice (closest being the
720K), then you may be able to use the DOS DRIVPARM command in your
CONFIG.SYS file to redefine the drive type after the BIOS flubs it.

From the rest of your description it sounds like the drive is addressed
properly.  One more thing to check is that the terminating resistors on
the floppy drives are installed properly.  Only the drive at the farthest
end of the calbe is supposed to have the terminators installed.  I have
gotten away without worrying about this in mixed 3.5"/5.25" setups, but
perhaps your floppy controller is less tolerant.

-- good luck, Steve Pacenka, Cornell U.