BA23 Box with RLV11 (Was: 11/23+ box with Microvax Memory)

Jerome H. Fine jhfinedp3k at
Tue Mar 8 06:41:06 CST 2016

 >jwsmobile wrote:

> I see on the usual site, an 11/23 box with a couple of random boards, 
> one of which is an M7608 board.  This is a Microvax memory board.
> I wonder if one can build up a Microvax in that backplane, or if that 
> is not recommended.  It would obviously be an 18 bit backplane.  The 
> backplane is H9276A.
> The auction also has a M9047 Bus grant card in it, so is essentially 
> just the box.  But I'd never seen Microvax parts plugged into those 
> backplanes, and it made me think.
> thanks
> Jim

Probably not as unexpected, but just as unusual in my mind:

I once saw a BA23 box with an M8190-AB (PDP-11/73) CPU
in slot 1 followed by an RLV11 (M8013 / M8014) in slots 2 / 3
connected to an RL02 drive.  Usually, by the time a system
had a PDP-11/73 board, a couple of MB of memory and an
RL02 drive, the RL02 controller was upgraded to an RLV12
(M8061) board.  NOTE that slots 2 / 3 had to be used for
the RLV11 since they were the only 2 slots left with ABCD.
Placing the RLV11 in any other position in a BA23 box lets
out the magic smoke.

As a bit of additional information, the other 5 slots were used
to hold the memory and other modules that were required.  There
did not seem to be any problem with the memory being placed
in slot 4.

Jerome Fine

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