22 Nov
2007
22 Nov
'07
7:37 p.m.
Message: 10
Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST)
From: Fred Cisin <cisin at xenosoft.com>
Subject: Re: FD400 drive troubleshooting
Many/most drives have 50Hz/60Hz zebra discs on the
flywheel, for using a
flickering fluorescent light.
Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM
strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM.
FWIW,
m