Here is the webpage where I tell exactly how to mod the DECserver CPU into
an 11/53.
http://users.safeaccess.com/engdahl/KDJ11.htm
In short, you have to reburn the ROMs, and solder in a 1K resistor. On the
old (.5 meg) boards, you also have to cut a jumper.
And here is the best example of the result to date (this is the description
page for the system I just eBayed):
http://users.safeaccess.com/engdahl/ebay/PDP-11_53.htm
Most of the DECserver boards I have found have 1.5 megs of RAM, late
revision CPUs, and 18 MHz cystals. Last week I got one of these for $5 on
eBay. Using a complete rebuild of UNIX as a benchmark, such an 11/53 is only
about 20% slower than an 18 MHz 11/83 with PMI memory. When I "diff -r" two
directory trees, the 11/53 is actually significantly faster.
I drill off the S-box handles, and replace them with a standard latch from
the stock that I got from Ethan. My web page shows how to build the console
cable. I have the user guide for this board. Does someone want to scan this
and put it on the web?
You can drill the handle off a DESQA, install a standard latch, short out
the fuse connector, carefully disassemble the AUI connectors, and replace
the AUI ribbon cable with a longer one. The result is identical to a DELQA.
RQDX3 are cheap and easy to find. The only really difficult part is finding
(large)hard drives. For that, I've figured out how to use other Maxtor
drives (see
http://users.safeaccess.com/engdahl/xxdp.htm). But even the
substitutes are hard to find.
--
Jonathan Engdahl
http://users.safeaccess.com/engdahl
"The things which are seen are temporary,
but the things which are not seen are eternal." II Cor. 4:18
----- Original Message -----
From: "McFadden, Mike" <mmcfadden_at_cmh.edu>
To: <cctalk_at_classiccmp.org>
Sent: Thursday, February 27, 2003 10:35 AM
Subject: decserver 550 in Kansas City
> Wandering through the local surplus I found a decserver 550 in a full
height
> rack.
>
> It had the following boards in it.
>
> 4 X CXA16-M M3118
> 1 X DESQA-SA M3127
> 1 X KDJ11-SD M7554
>
> Bulkheads, power supply, and cables
>
> I read somewhere that it could be converted to a 11/53 with a minimal
> effort. How much trouble?
>
> Mike
>
> m m c f a d d e n _at_ c m h . e d u
Received on Thu Feb 27 2003 - 23:38:00 GMT