Working 8" Floppy drives??? - test-drb@ccmp.vtda.org

8 May 2003

On May 8, 11:09, Ethan Dicks wrote:
...
  --- "Fred Cisin (XenoSoft)"
&lt;cisin(a)xenosoft.com&gt; wrote:
 > On Wed, 7 May 2003, Nick Garnett wrote:
 > > Does anyone know the whereabouts of any working 8" floppy
 > > drives?
 > Have you considered substituting 1.2M 5.25" drives?
 > Once you make the appropriate cables and jumpering, they will usually
...
   work as a
drop-in replacement, with NO software changes. 
 Serious question (not meant to merely contradict Fred), what would it
 take to do that for an RX01 or RX02?  The drive mechanism itself in
 a DEC 8" drive has no electronics - it's a motor, a head loading relay
...
  (the drive motors spin whenever the unit is powered
on, unlike modern
 equipment), a couple of sensors and a head cable.  All of the "work" is
...
  done on the board above the drives. 
There might be issues around matching the head's impedances etc to the
preamps and drivers on the RX01/2 electronics, and possibly even around
the step angle of the positioner, but nothing inssurmountable, I
suspect.

...
  Even getting past electrical issues, one trick would
be how to low-level
...
  format the disks. 
Not too hard.  An RX01 floppy is a standard format; you could do it on
any CP/M machine that exepcted 8" drives but actually had a suitable
5.25" drive, or on a PC with a suitable FDC and suitable version of DOS
(or Linux, probably), or indeed on many other systems.  Once formatted
to single density (RX01) most DEC system can then "reformat" the disk
as RX02 (modified double density).

...
  Among other reasons for doing it is that I have an
RX01 that came from
...
  a client with a siezed rotation motor on one drive and
a siezed head
 positioner motor (with attendant incinerated head motor driver
 transistors) on the other drive.  Yes, I can repair the transistors and
...
  move one good motor to the other mechanism, but it
means that I have 1/2
...
  of a full RX01. 
I had a drive motor seize on my RX02.  It wasn't all that hard to free
the spindle, clean the bearings, and re-lubricate them.  It's running
fine now.  It's certainly worth a try.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York