Thanks Josh. If it's just physical (ie. just need a longer cable) that could be easily done. Nowhere is it stated what the max. length of this cable is, but seeing how it carries the 32 bit data lines, it should be as short possible. In the enclosure the second and third slots are for memory, so it should be able to be at least as long as from the third slot to the CPU board. That might give enough slack to account for the different position of the 50 pin header. The KA630 manual seems to imply that the max. amount of RAM is capped at 9M (1M onboard + 2x4M cards), yet DEC 8M cards are available. Can two 8M cards safely be put in the BA23 for a total of 17M? -- alex ----- Original Message ----- From: "Josh Dersch" <derschjo at gmail.com> I seem to recall that the physical positioning of the 50-pin headers on the KA650 and KA630 module (and their associated memory boards) are different, so it's physically difficult to connect mismatched boards (without rigging up a different cable). However, it's been awhile since I've fooled with this. Based on this I'd wager that they're incompatible but I can't say I have conclusive data/experience to back this up. (Compare the images at: http://hampage.hu/dr/kepek/ka650.jpg vs. http://hampage.hu/dr/kepek/ka630.jpg -- the positioning of the 50-pin header - Josh

As I understand it (I'm sure I'll be corrected if I'm wrong), two 8M cards will work, though the total will be only 16M because the KA630's hardware has only 24 address lines at the relevant place. (I don't know which meg will go unused; my guess is it will be the high meg of one of the 8M cards, but that's just a guess.) /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTML mouse at rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

I haven't had much time to spend here lately, But I have extra's of most of these. If anyone is interested, please contact me off list. Paul On Fri, Mar 21, 2014 at 9:37 AM, Jonathan Katz <jon at jonworld.com> wrote:

Glen, I have the KA630 cpu (you probably figured that one out, after the SIMH posts on srcs) and a M7608-BA plus a M7609. It seems that there are more 7621's floating around than 7609's. I plan on eventually replacing the 7608 down the road. that's why I asked the question. thanks -- alex ----- Original Message ----- From: "Glen Slick" <glen.slick at gmail.com> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Sent: Thursday, March 20, 2014 5:30:14 PM Subject: Re: microVax II memory question If all you have is an M7606 KA630 CPU board and an M7621 MS650 8MB memory board, it shouldn't be too hard to find either an M7609 MS630 8MB memory board to pair with the M7606 KA630 CPU board you already have, or an M7620 KA650 CPU board to pair with the M7621 MS650 8MB memory board you already have, to end up with a matching CPU and memory board set. My guess is that there are more than a few spares of these collecting dust out there with members of this list. -Glen