formatting MFM drives on a IBM PC

Mike Stein mhs.stein at gmail.com
Thu Sep 28 12:21:13 CDT 2017


----- Original Message ----- 
From: "Al Kossow via cctalk" <cctalk at classiccmp.org>
To: <cctalk at classiccmp.org>
Sent: Thursday, September 28, 2017 12:17 PM
Subject: Re: formatting MFM drives on a IBM PC


> 
> 
> On 9/28/17 7:38 AM, Mike Stein via cctalk wrote:
> 
>> What is it that usually fails when the drive can't read the servo info? The data on the platter, or?
> 
> I've never dug that far into it beyond fiddling with Micropolis trying to mechanically get it to
> find the servo tracks and calibrate to track 0.
> 
> One of the problems is schematics and documentation on the servo systems are extremely difficult
> to get. The little that is on bitsavers is all I've come up with in 25 years of searching and there
> is practically nothing useful elsewhere on the web about fixing servos in old 5" disks.
> 
> It could be heads, media, positioners, component aging in the analog section, etc etc..
> 
-------------
Too bad. I'm probably not the only one who has drives that sound fine (i.e. no bad bearings, scratched surfaces etc.) but will not initialize; they twitch back and forth on startup, presumably looking for track 0, and then give up.

Seems like a shame to scrap them if only there were some remedy...

m


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