FD400 drive troubleshooting
M H Stein
dm561 at torfree.net
Sat Nov 24 00:40:39 CST 2007
> Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST)
> From: Fred Cisin
> 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.
I think you have the ratio backward. The 60 Hz disk for 360 RPM
can be used for the 50 Hz 300 RPM.
Well, unless you're just saying that a 60Hz 360RPM strobe disk (if you had one)
would also sync at 300RPM under a 50Hz light, I don't see what's backward.
The point was that 50/60Hz 300RPM strobe disks are common, and if you're in
a 60Hz zone you can use the same disk for 8" and dual-speed drives as well.
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