Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!ucbvax!XEROX.COM!"Hugh_E._Wells.ElSegundo"
From: "Hugh_E._Wells.ElSegundo"@XEROX.COM
Newsgroups: comp.sys.atari.8bit
Subject: XF-551 Disk Drive
Message-ID: <890815-120454-16753@Xerox>
Date: 15 Aug 89 15:43:42 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 43

I received a note requesting more info on the sleeping problem of the
XF-551. I responded directly to the writer but my message did not go
through and was returned for some reason.
---------------
 The original posting is as follows:

"It appears that the XF-551 disk drive has an inherent controller board
problem which causes the drive to go to sleep.  This caused me to open it
up and attempt to find the difficulty.  I really need a schematic diagram.

Although I haven't located the problem as yet, I did notice that the drive
mechanism is a standard IBM 1/2 height 5-1/4 drive which is easily replaced
-- plug compatible.  I appreciate that fact as 1/2 height drive mechanisms
are readily available.

I would appreciate any info available on XF-551 schematic diagrams and/or
how to resolve the sleeping problem."
--------------

For additional info, I'm aware of three XF-551 drives owned by three
different individuals that are experiencing sleeping type problems.
Judging from that I would expect a design flaw to be the cause.  My
particular drive had a sleeping problem which was intermittant at first
where the drive failed to react to a command for short periods, but
otherwise worked correctly. 

Now, my drive has degraded to the point where it fails to respond at all.
I have diagnosed the problem to the extent that it is the controller board
at fault and not the mechanism/board.

To solve the problem, would be for Atari to design a fix for the sleeping
condition.  The chances of that happening, I expect, are pretty remote.
Therefore, I would settle for a schematic and/or a replacement controller
board.

Any assisstance in obtaining troubleshooting info, schematic, replacement
board, etc. would be much appreciated. 


Thanks,

Hugh Wells
(213) 333-7923