New subject: VaxStation 2000 as an MFM formatter (was RE: TCP/IP for VMS 5.4)

14 Jul 2009

...

Subject: RE: TCP/IP for VMS 5.4
   From: "Zane H. Healy" <healyzh at aracnet.com>
   Date: Mon, 13 Jul 2009 10:46:51 -0700 (PDT)
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

On Mon, 13 Jul 2009, Robert Jarratt wrote:

  You are right about the RD53s though. The one
that came with the machine
 seemed a bit dubious to me but seemed at least to respond in some way (I
 could start a boot but it would never complete). Then one day it just went
 offline as if it is not attached at all, I wonder if this is not a
 mechanical problem but an electronic one in this case? Is there anything
 that can be done to revive them? 
Most likely you've run into the sticky pads problem.  Hopefully Allison
answers this, as I believe she has experience reviving RD53's.  IIRC,
basically you open the drive up and remove the sticky rubber pads.  I really
don't remember the details as I went SCSI nearly 10 years ago.

Zane

If it spins up then back down and repeats thats a stuck head positioner.
When the drive is powered down there is a magnetic retract and at the 
end of travel there are bumpers that betwen heat and time get sticky.
The windup then down is the failure of the heads to move and find servo
and it fails.

There are two fixes, temprorary is to freeze the drive and sometimes 
they unstick.  Me I open the drive, unstick the heads and reach in to
the mech and pull out the goo they stick too.  Never had a failure yet
and all 6 of my RD53s are salvaged this way and most were opened over 
10 years ago (two approaching 15!) and they are well past their MTBF
now.  I haven't opened any in years since I haven't found more and 
generally RD53s are more useful to me as spares, swap or for the Qbus
pdp 11s I have. Other than that goo problem they were otherwise 
reliable drives. 

I also have a boat load of RZ22,23,25, RZ55 and RZ56s in use and a pile of 
RD52s (quantumn D540s).  The RD52s are only 31mb but perfect for swap or RT-11
based systems as they were very fast for their storage size and unkillable.
I have better than 12 of the D540s as I use them in CP/M based systems as
well. 

For backup I use the RZxx as backup as they are faster and more 
reliable than TK50. TO create a new system I do a backup/image to 
a same size or larger to clone the disk and system. Same for the 
MFM drives.  Old 1gb SCSI Baracuda drives are excellent for MV3100s
and anything with SCSI and the run forever.

If you going to mess with MFM drives you must have a MicroVAX2000 as its
a good RDxx formatter in a box (RqDX3 compatable). If it has decent amount
of memory and an RD54 in it they can be fun to play with as they are 
small and very portable.  The alternate is to MOP load VMS to it and use a
small 20-40mb disk for local files and swap.  With two you can run LAVC!

Allison