I am having trouble with SCSI on a Mac IIfx. The machine is 3 years old
and I have been using the same hard drive (internal Maxtor LXT-200S) for
two and a half years. The disk recently crashed. I reformatted (Silverlining
5.42), but during the reformat I received random write errors during testing.
The error message reported was like:

Sector 0: Write error detected after testing good - sector not mapped out.

This occurred randomly all over the hard disk (which makes me suspect the
diagnostic's reference to Sector 0 ??? ). On the third reformat and after
reinstalling the SCSI read/write loops I was able to get through passes
2,3, and 4 with no errors. (Pass 1 for some reason reported a lot of errors,
but still mapped out no sectors.) I decided to go ahead and try to resinstall
System 7 and reload my data from a backup. This proceded normally; however,
I now have sub-optimal performance. Symptoms include:

   o Frequent crashes
   o Instances of extremely sluggish disk access requiring a reboot to
       correct.
   o Instances of not finding the disk on the SCSI chain on reboot.
       - If I boot from Norton Utl. after this occurs, it cannot find the
         disk either.
       - The only thing that fixes this is recycling the power. It sometimes
         requires several attempts.

QUESTIONS:

   1) Has anyone had this type of problem before?
   2) Is the problem with the fx motherboard (And its non-standard
      SCSI implementation) or with my Maxtor Disk? Is there some
      diagnostic software that would help me make this determination?
   3) Is it a termination problem? I currently have external Syquest
      and an external DataFrame XP60 on the chain. The XP60 is at the
      end, and has internal termination; so I am not using the IIfx
      terminator. I do have the SCSI filter installed on the internal
      drive. I have run with this exact steup for 2 1/2 years with
      one previous disk crash requiring a reformat (about a year ago).
      I also have symptoms if I disconnect the external devices;
      so I don't see how SCSI termination would now be an issue. Of
      course who knows :-<

Help would be much appreciated.