Subject: Re: Perking up the MVII with MVII boards and bits?
To: NetBSD Bob <>
From: Chuck McManis <>
List: port-vax
Date: 01/26/2001 10:25:48
At 01:04 PM 1/26/2001 -0500, NetBSD Bob wrote:
> > A MicroVAX III, I've got one in da' house (named it HalfVAX) Mine came in
> > the "dual BA23" mode which has two BA23 cabinets mounted in the rack on 
> top
> > of each other and a double high swinging back door that holds all the end
> > plates.
>OK, for the sake of discussion, and mixing/matching/gooping up parts to
>make a best/fast BA123 configuration for NetBSD use..... I have.....
>1.  BA123 cabinet with SQ706A and 4 scsi drives, and TK50 tape/card.
>2.  KA640 CPU and ram boardset from an MV3300 (the cabinet currently is
>     running my spare MVII boardset for tesing NetBSD).
>3.  KA650 CPU (I am hoping) and maybe other ram in the VAXstation 3200
>     I picked up today.
>Now, I would reason that I could drop the KA640 ram boards and VS3200
>ram boards sufficient to max out 3 boards, and the KA650 CPU into
>the old MVII BA123 cabinet, and whip up a best/fast VAX.

I think so. The RAM is compatible, however Both the KA640 (MV3400) and 
KA660 (4000/200) have the "s-box" console connector which means they are 
not compatible with the standard BA{1}23 cabinet kits*.

With more "commonly" available parts, the bestest/fastest VAX you can build 
in the BA123 is a MicroVAX 3800 using the KA655 cpu card. Remember that 
this requires MS650 memory (ECC) rather than MS630 memory (Parity).
As with the KA660 I've discovered that off brand MS650 memory that works 
with the KA640 does not always work with the KA655 or KA660.

>Then, sift out the second level KA630 boards to put into the MV3300
>chassis to maximize that.  It is sort of spread-eagled, since I have
>not got any of the right bits for that cabinet to make it work
>correctly.  But, it works.

I take it I need to send you the cab kit that would let you hook up that 

>Then, drop the remainders into the BA23 cabinet.  This would be the
>least of the least of the least VAXencritters.

Just document what you've done so you can reconstruct it later. I've put 
more notes into the DEC supplied "Micro Site Guide" attached to my VAXen 
than the Field Service guys ever did!

>Does that sound reasonable?

Sounds like fun anyway. Always bring modified vaxen up a few bits at a 
time. This avoids having it be completely non-functional for no apparent 

>Hopefully, that would get over some of the slowness in MVIIland I am
>experiencing, but, still retain a couple of MVII boxes for testing.

Oh definitely. I can completely rebuild NetBSD 1.5 on my 3400 in under a week.


* In an interesting but definitely weird bit of luck I actually picked up a 
4000/200 that had been in a BA23 and there is a very strange DEC cab kit 
for it that works in these cabinets (its got three plates, DSSI plate, 
Ethernet plate, and CPU console plate) I'm going to be able to make a VAX 
4000/200 in a BA123 with this :-)