Re: MFM drive gone nuts

From: Gerrit Heitsch <>
Date: Sat, 19 Jul 2014 19:51:39 +0200
Message-ID: <>
On 07/19/2014 07:38 PM, Michał Pleban wrote:
> Remember again that this is without the controller attached. Attaching
> the controller, the controller to the computer etc. has no effect. The
> computer is unable to communicate with the drive as it performs its head
> dance - all operations result in timeout.
> Do you possibly have any idea what is going on with the drive? I thought
> that maybe it doesn't like the voltage from the CBM710 PSU, but I doubt
> it - the whole computer runs on it flawlessly (including the floppy
> drive). Or maybe something was broken when I attached the CBM610 PSU and
> learned that it is too weak to spin the drive? But in any case, this
> would be very strange symptoms of a power failure.

All the drives I have seen have some kind of microcontroller on them. 
Along the lines of a 8049 or 8051. Take a closer look what you find on 
your drive. Could be an EPROM-based controller (e.g. 8751) that is 
slowly losing the contents of the EPROM part due to age.


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Received on 2014-07-19 18:00:33

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