farris@marlin.NOSC.MIL (Russell H. Farris) (04/03/91)
I added a Chinon 1.44mb disk drive to my single-drive Sharp
PC-4501 laptop and now the computer behaves very strangely.
Either drive will work fine as A:, but neither will work
correctly as B: (or C:, or D:, etc.). CHKDSK works for B: and
identifies it correctly as a 720k drive, but when I use DIR it
says B: is "not ready." I can COPY to B:, but I can't DEL files
from it.
I am using a flat 34-pin cable with pin 15 clipped out (as
in the original Sharp cable). Drive selection is by means of
jumpers/switches. I am using MSDOS 3.3 and have tried the
following lines in my CONFIG.SYS file.
device=driver.sys /d:1
device=driver.sys /d:1 /f:2
drivparm=/d:1
drivparm=^a/d:1 /f:2
There is no drive connected to the EXT FDD port, but I am
beginning to wonder if there is a some kind of conflict between
FDD drive assignments.
Sharp will not sell their service manuals to individuals
(remember that when you think about buying a Sharp product) so
I'm completely stumped. If you have had any success in solving a
problem like this, your help would be greatly apreciated.
Thanks,
Russ Farris (farris@marlin.nosc.mil) (619) 553-4129ardai@teda.Teradyne.COM (Mike Ardai) (04/04/91)
In article <1737@marlin.NOSC.MIL> farris@marlin.NOSC.MIL (Russell H. Farris) writes:
-
- I added a Chinon 1.44mb disk drive to my single-drive Sharp
-PC-4501 laptop and now the computer behaves very strangely.
-
- Either drive will work fine as A:, but neither will work
-correctly as B: (or C:, or D:, etc.). CHKDSK works for B: and
-identifies it correctly as a 720k drive, but when I use DIR it
-says B: is "not ready." I can COPY to B:, but I can't DEL files
-from it.
-
- I am using a flat 34-pin cable with pin 15 clipped out (as
-in the original Sharp cable). Drive selection is by means of
-jumpers/switches. I am using MSDOS 3.3 and have tried the
-following lines in my CONFIG.SYS file.
I have successfully added a 720k drive to a 4501. In order to
'force' you to buy drives from Sharp, they have messed around
with the drive select scheme. It has been a while since I did this,
but as far as I remember, one of the drives is selected by
'drive select' and the other by 'motor enable'. What I had to
do was to clip drive select on b and connect it to motor enable
on b (I think. it may have been the other way around.) Just
probe around with an LED while doing 'dir a' and 'dir b' to see
what is really happening.
/mike
--
\|/ Michael L. Ardai Teradyne EDA East
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