[rescue] MicroVAX II CPU upgrade KA630 to KA650 possible?

saquinn624 saquinn624 at aol.com
Fri Jul 31 11:22:00 CDT 2009

On Jul 30, 2009, at 5:15:22 PM, rescue-request at sunhelp.org wrote:

Message: 2
Date: Thu, 30 Jul 2009 12:56:34 -0600
From: Scott <scott.mickey.sunhelp at atsgate.com>
To: rescue at sunhelp.org
Subject: [rescue] MicroVAX II cpu upgrade KA630 to KA650 possible?
Message-ID: <4A71ECE2.123F1E6 at atsgate.com>
Content-Type: text/plain; charset=us-ascii

I've got a MicroVAX II that has these cpu and memory boards: 
- M7606 CPU 
- M7608 4MB Memory 
Can I pull these and install: 
- M7620 CPU 
- M7621 Memory 
No other qbus cards will be changed. 
Seems it should work, but I'm not sure if the backplane will allow it. 
All of the Q-22 MicroVAX/VAX processors (up to KA660) can be interchanged this
way. You don't get the backplane-routed DSSI that you do on VAX 4000/200 KA660
machines, but it works.

What would be cool would be if you could cut traces or similar to have 2
KA660s in a single BA430 running as a DSSI VAXcluster. Should theoretically be
possible, but I don't have a spare KA660 to try it with. All you'd need to do
is find out which of the C/D lines the DSSI went out on and cut the other
traces (PMI, etc.). To make things easy the A/B Q22s should be cut, too, but
leave the power and DSSI lines. Right?

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