Date   : Tue, 21 Aug 1984 08:37:39 EDT
From   : Dave Towson (info-cpm-request) <cpmlist@Amsaa.ARPA>
Subject: [Drsel-Tcs-Sio: Re:Osborne 1 disk drive problems]

Send replies to the originator of this message, not info-cpm-request.


----- Forwarded message # 1:

Received: From cecom-1.arpa.ARPA by AMSAA via smtp;  20 Aug 84 14:57 EDT
Date: 20 Aug 1984 1458-EDT
From: Drsel-Tcs-Sio@CECOM-1.ARPA
Subject: Re:Osborne 1 disk drive problems
To:   INFO-CPM-REQUEST@AMSAA.ARPA

I had a similar problem with my Osborne1 "A" (left) drive.
The drive would sound erratic, the (internal) CRT would 
be affected, it would produce (what started to be occasional 
and eventually became continual) boot errorsa, and it  
would lock up the drive .  I found I could still force it 
to operate by opening th e drive door, taking out the diskette,
and spinning the drive with my finger.  This technique worked
o.k. as a emergency quick fix, but is not recommended for 
the health of your system.  I then would re-insert the diskette,
and the system would continue (ussually), or totally crash 
(once in a while).  Finally, during a period where I was 
desperately trying to geet my machine back in operation, and 
not finding any local reapiar place willing to do the work
(including Xerox), I dug in with the O-1 Technical Manual 
and a friendly EE technical advisor.  The result was to 
discover an excessive ammount of "noisew" (using an oscilloscope)
in the drive controller board going to and comming from the 
drive motor.  Feling very adventurous and without any re-
course (it couldn't get worse), wew tll we took the drive motor
out, disassembled it , cleaned it (it was carboned heavily
and had some metal falacks in it) and put it back.  Believe
it or not, I was delighted to find it worked, and all my
problems had been solved.  kSince then I have found that 
Priority -One Electronics (see any Byte mag) is supposed to
carry parts for MPI disk drives, and should be able to replace
yours if you want to try this route.

I have been operating my O-1 frequently for over a month now 
and it still seems to be fixed.

----- GOOD LUCK !! -----   Todd Kersh, 
                            DRSEL-TCS-SIO at CECOM-1.ARPA

----- End of forwarded messages