[comp.sys.ibm.pc.hardware] Problem.....seeking solution

elev50@castle.ed.ac.uk (N Porfiris) (12/07/90)

Hello,

I have got a peculiar type of problem with a 386 SX and I am seeking for
a solution. The problem is  as follows:

-the hard disk is a Fujitsu IDE, 90Mb, 25msec
-there is only one DOS partition
-the drive A is a TEAC 1.2Mb
-the drive B is a TEAC 1.44Mb
-the BIOS is AMI BIOS
-the OS is MS-DOS 4.01

The problem: 
       |      BOTH drives function ok with 1.2 and 1.44 diskettes
       |      ^^^^
       v
While using 360Kb and 720Kb floppies: 
            ^^^^^     ^^^^^
          1. BOTH drives are successfully reached when I try
             the commands  'a:' or 'b:' from the c:
             
          2. BOTH  drives successfully display the directory 
             contents when I try ' dir a: " or 'dir b: ' from 
             the C: 

          3. BOTH drives give "Abort,Retry or Fail" message when I
             try the command 
                ' copy a:*.* ' or ' copy b:*.* ' from the c:
             This appears after 65.024 bytes are copied either
             from the first file if it is longer, or more files 
             until this limit of 65K is achieved

          4. BOTH drives  display 'invalid media' message when I
             try the 'chkdsk a:' or 'chkdsk b:' from c:

          5. After this error, steps 1. and 2. fail unless I release 
             the drive's lever and reposition -out and in- the floppy 

          6. Copying works sometimes ok if using the XCOPY command

          7. I have found out that copying can be performed successfully
             in 65.024kB cycles, that means by pulling up the lever,
             repositioning the floppy and pressing retry....until the 
             whole floppy is copied.

          8. INT 24  error   appears if Fail is chosen after the error 
             message appears.

          9. Format command works fine but still the 360 or 720 floppy
             so formatted, give above mulfunctions

What I have tried so far:

          1. Checked the drives with the installed test for random 
             and sequential read and write.   ok
                                              ^^
          2. Checked the drives with a program called CHECKIT. ok
                                                               ^^
          
          3. I have taken off both drives and the controller( there
             is one card controller for hard disk and drives ) and
             chequed both drives on the motherboard of a GOLDSTAR
             386 SX whith 360 and 720 floppies, where there was no
             problem.

             I then added my hard disk on that motherboard and I did
             not have any problems.

             Can it be my motherboard ...?? that causes that problem
             or what on earth.........

            (my motherboard is a SHUTTLE 386 -16 )

       Anybody who can help , welcome

                                            Nicos Porfiris
              e-mail : elev50@castle.ed.ac.uk