Date   : Tue, 06 Dec 1988 04:31:40 GMT
From   : cleopatra.usc.edu!mlinar@oberon.usc.edu (Mitch Mlinar)
Subject: floppy shut downers

In article <5543@cadnetix.COM> rusty@cadnetix.COM (Rusty) writes:
>In article <4000@drivax.UUCP> riddle@drivax.UUCP (Riddle) writes:
>>I'm looking for two related products/projects/circuits/designs that I could
>>buy or build.  Both are needed for several 8 inch floppy drives I run.

I adapted a design some umpteen years ago that controlled standard 8" drives
which had no motor control.  I am talking about the older AC drives (such as
Shugarts).

The circuit, which was published at that time in my column in MicroCornucopia,
used the select lines from a Xerox/Kaypro to determine if the motor should
be spinning.  Since the select lines in these machines is an artifact of the
ROM (direct control of side select and drive, not through a disk controller),
timeout was handled on the BIOS side of things.  The circuit is easily adapted
to have its own motor timeout, though.

The circuit - at that time - consisted of a triac, diac, optoisolator, and a
of couple capacitors, resistors, and diodes for TTL logic to control AC.
This can probably all be done in one hybrid part these days.

I have been using this circuit in two different machines pretty much daily
for 6 years now with no problems.  I *will not* tolerate drives that spin
when not active.

By the way, how much for the SA850/851 2-drive combo?  Power supply and
cabinet included?

-Mitch