More mystery recycler boards - DEC, Fujitsu(??), Cipher, Emulex

Pete Turnbull pete at
Wed Sep 7 03:58:57 CDT 2016

On 07/09/2016 03:32, Jules Richardson wrote:
> On 09/06/2016 08:58 PM, Noel Chiappa wrote:

>> As far as I know, all the M8190's are _basically_ the same: they are the
>> KDJ11-B CPU, which support the PMI memory bus, can operate with a
>> KTJ11-B to
>> provide a UNIBUS, etc. They are the CPU in an 11/83 (with QBUS only
>> backplane) and the 11/84 (with QBUS/UNIBUS backplane).

> I got the /73 reference from a post of Pete's last year:
> ... but I' m guessing he just meant that the slower ones work at the
> same speed as a true /73?

Well, in a sense the slower ones /are/ 11/73s.  By that I mean that all 
the microPDP-11/73s that DEC sold were (AFAIK) running at 15MHz and all 
the 15MHZ boards were sold as 11/73s - but all microPDP-11/73 machines 
had an M8190.  The M8192 was mostly sold as an OEM board.

Don't believe (let alone rely on) the Wikipedia article about the 
PDP-11/73 - it's just wrong.

> Unfortunately there aren't any markings on the crystal on the -AB board
> (well, there probably are, but on the underside and it would have to be
> desoldered) so I don't know if it's a 15MHz or 18MHz part.

Look at the ROMS; if they're really early ones it's probably a 15MHz board.

Pete Turnbull

More information about the cctalk mailing list