[comp.sys.ibm.pc] floppy drive problems

readdm@walt.cc.utexas.edu (David M. Read) (08/19/89)

I have recently acquired a problem with my floppy drives, and was wondering if
anyone can suggest any do-it-yourself type fixes.

The problem is this:  neither drive will format disks; I always get a "system
reserve are bad" message, and the format aborts.  This happens on both drives,
with any disk (even new).  The wierd part is that if I Copy2PC a previously
formatted disk onto a target and then erase the files, everything is ok.

Since both drives started doing this simultaneously, I suspect the problem lies
in the floppy controller, but I'm not sure.  Could this be just an alignment
problem?

The machine is a 1984 Leading Edge PC (old, yes.  reliable up till now, yes.)

Does anybody have any ideas?  If all else fails, I'll take it to a repair
shop, but us poor starving physics grads are known not for high cash flow but
high ability to try anything.

Thanks in advance.

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David M. Read                        best -=>  readdm@snowwhite.cc.utexas.edu
                           all-else-fails -=>  read@physics.utexas.edu

"...[he's] stupid and he's ignorant but he's got guts...and guts is enough!"
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mdfreed@ziebmef.mef.org (Mark Freedman) (08/25/89)

(both floppy drives suddenly become unable to format disks)
    it IS possible that botn drives have worn out (heads, alignment, whatever)
at the same instant, but .....
     I once had a similar experience. After buying a box of Maxell disks (back when they cost $50 / box), a head cleaning kit, taking the system apart and 
watching the heads step through the format without any apparent problem, I
tried formatting with the FORMAT program on the original release disk, rather
than a copied work disk. 
   This worked perfectly. I then copied FORMAT to the work disk, and formatted
successfully using the copy.
    I have no idea how FORMAT became corrupt, but that's what appeared to have
happened (I believe that it happened several more times over the years, but
that was a while ago). If I recall correctly, it was PC-DOS 2.x, so it may
have had something to do with that, or with JFORMAT / QDRIVE (Tall Tree 
Systems software to format / access different disk formats).

nigel@nmtsun.nmt.edu (Nigel Sharples) (10/24/89)

A friend recently bought a 386SX machine - it refuses to format
a disk without marking off bad sectors (3.5" 1.44 meg drive).

I utilised its BIOS's 'format disk' function (AMI BIOS) which only
went to cylinder 39 before quiting and saying everything was fine.
Incidently, the BIOS does know that the drive is a 1.44 meg.  The BIOS
also has a sequential read/write test which it performed, only to fail
with a checksum error at cylinder 73.

Is the problem with the drive, BIOS, or both (or controller?....)

Any comments would be much appreciated!
Thanks in advance.

Nigel
-- 
   "Many's the night I've dreamed of cheese, toasted mostly."