Floppy drives for the Tarbell floppy controller

From: Barry Watzman <Watzman_at_neo.rr.com>
Date: Sat Sep 11 19:11:05 2004

Which Tarbell Controller?

There were 4 revisions of the single density board, A thru D, and way too
many revisions of the double density board (A thru H, but A thru D did not
work reliably; the revision "E" board was really the first version of the
double density board that was reliable). The single density Tarbell board
was a mess, it wasn't much more than a disk controller "prototype" board,
you basically had to jumper-wire the entire board yourself by hand based on
the type of drives that you had, it is just awful (typically, you ended up
installing something like 50 jumper wires). HOWEVER, if you got the board
jumpered right (and, of course, if the parts were all good and if it was
assembled right), it actually worked really well. The double density boards
ran way to hot, the voltage regulator was way over-stressed, and I always
put a low-value 2-watt resistor across the voltage regulator on the back of
the board (something like 10 ohms) to relieve a bit of the stress on the
regulator.

The single density board was an "early" item, before the drive interfaces
became relatively standard. Because of the jumper options, it could be
modified to take ANY drive.

The double density board basically requires either a Shugart type drive (or
one very compatible with it), or a Persci drive. There were only a
relatively few jumper options.

Manuals for both boards are on Howard's site.
Received on Sat Sep 11 2004 - 19:11:05 BST