Mounting a SCSI Device in a BA-123

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Sat Jul 28 01:28:54 2001

At 10:59 PM 7/27/01 -0700, Terry wrote:

>Has anybody ever mounted a SCSI device in a BA-123?

Yes.

>1. I tried to install a standard half-height 3.5" SCSI drive into a
>BA-123 system (MicroVAX II). Basically, I bought a little 3.5"->5.25"
>adapter, and then screwed the adaptor into the sliding base where an old
>RD-54 lived. I found the solution unsatisfactory; the adaptor's screw
>holes did not match up with the sliding base, and it generally feels
>fragile. Is there a better way? I am envisioning some sort of "cage" which
>has the form factor of a full-height 5.25" drive, with mount points for a
>3.5" drive (or two). Does such a beast exist?

I don't think a 3.5" one exists but the half height 5.25" ones do. (lets
you mount two 5.25" disks on a sled. If I were going to do this (and I
wouldn't, instead I'd put a dirt cheap full height SCSI drive in there ;-)
then I'd get a scrap piece of aluminum, drill out a hole pattern to match
the bottom of the 3.5" drive counter sink four holes and mount the drive,
then drill and tap the aluminum at the spots needed on the sled. Then mount
screws through the sled into the aluminum plate.Should be both sturdy and
durable. If you use angle aluminum you could build a two (or three!) drive
stack system.

>2. Has anybody ever installed a half-height internal CD-ROM (or tape
>drive) in a BA-123 system? This would be really sweet (sure beats an
>external one!), but would it mount nicely, and would it be possible to
>cover up the half which isn't being used with a nice faceplate?

A couple of choices here, the easiest is to get one of the blank covers
that DEC used and carefully mill out the opening where the drive would go.
Alternatively there are full height to half height bezel adapters. Not
common but I see them off and on at the surplus shops.

>3. Is there a decent internal SCSI cable which can be used in a BA-123? I
>only have a couple of boards in the system, so my SCSI controller is all
>the way in the front of the backplane (back of the system), far from the
>disks, and just barely reaches the disks. Is it possible to get one with
>some slack, and still have several disk connectors?

Not "retail" since they assume you are mounting the thing in a PC. However
you can pretty easily build your own cable with a vice and some IDC
connectors and length of ribbon cable. Alternatively you can run to a
connector on the bulkhead and mount your SCSI drives in an external box.
Or, as I've done, run the cable both to the bulk head and to the internal
drive. Then the CD-ROM is external (I share it between VAXen since its a
waste to have it attached if I don't need to mount CD media right then and
there)

--Chuck
Received on Sat Jul 28 2001 - 01:28:54 BST