🚀 go-pugleaf

Please help me with a sad Mac problem.  The machine is an old 512K
fat Mac with 64K Roms and 400K internal drive.  Upon powerup, the
disk grinds for a while and either ejects with "X" or gives a
Sad Mac 0F0064, depending upon the disk used.  Sometimes every-
thing works fine!  Other times, all works well until an application
is quit, and another disk inserted.  Doesn't seem to be correlated
with any particular disk.  When it does work, there's no problem
with any particular application, even Ram Disk.

Could this be a filthy disk head?  Could it be power-supply related?
The computer has never had any other problem, and this only showed
up after insertion of an MEI generic disk.  Could the disk have 
damaged the drive??

Thanks in advance.

[All opinions herein are my own or borrowed.]