[cctalk] Nuking an MFM drive with a magnet, format/servo gone?

[Chris Zach via cctalk]

Question: I just used a strong magnet to wipe an old Maxtor MFM drive 
(magnet on outside of case). Now the drive will not even seek properly 
on start up, just endlessly moves the heads..

Is the drive now toast? Do MFM drives have embedded servo information on 
the platter formatted by the factory?

CZ