DecServer 550 chassis

jwsmobile jws at
Mon Oct 19 13:57:30 CDT 2015

On 10/19/2015 10:03 AM, Johnny Billquist wrote:
> Not sure what you expect a "conversion" means. Creating new PROMs 
> imply finding actual proms, a prom programmer, the code to program 
> into the PROMs, and then just replace the proms on the card.
> Only the last piece will actually require any modification of the 
> card, and I would expect them to be socketed anyway, so replacing 
> means just removing the old proms, and inserting the new ones.
That is basically what I said.  I don't have one that isn't part of a 
DecServer and i need images, or someone with a non DecServer to provide 

I guess you restated what I said.  if you have one, I'd appreciate copies.

I didn't post the original link from the top of this thread, you might 
want to read it.  I'm just stating what someone did back in the 2001 
time frame and posted a page about the conversion and info on his 

> The note also mentioned that you might want/need to install a pull-up. 
> But it would still be an extremely simple process. You just need the 
> right bits...
What I said.
>     Johnny
> On 2015-10-19 18:28, jwsmobile wrote:
>> I would appreciate thoughts on the conversion of the processor to normal
>> PDP11 eproms.
>> The page pointed to earlier has a mention of that too, but the poster
>> had access to another "real" KDJ and I am guessing copied that.
>> I don't have access to any version of the system with appropriate eproms
>> and would appreciate any pointers to the binaries needed.
>> As to the condition most of the material is the result of moving it from
>> where it was stored.  It will be totally disassembled and tested before
>> being brought back up.  There is about 5 or 6 large deep freeze (for
>> reference) sized piles of material being sent for e-waste from the place
>> that is pretty much just junk material under the weather.
>> Think of this as a Dusenberg rescued from a barn though.
>> thanks for all the suggestions and observations.
>> Next thing to go over is a Sun 4/260 "mini" tower.  Gads those were
>> heavy.  Back is still aching from moving that.
>> Jim
>> On 10/19/2015 7:32 AM, Ethan Dicks wrote:
>>> On Mon, Oct 19, 2015 at 3:42 AM, Pontus Pihlgren <pontus at>
>>> wrote:
>>>> Interesting. I thought Tthe DECserver 550 was merely the big 
>>>> brother in
>>>> the terminal server line. But it looks like it is essentially a
>>>> PDP-11/53 with 1.5MW of ram, you need new boot roms though. Pretty 
>>>> nice.
>>> Yep.  It's essentially an S-box KDJ11 with different ROMs.  I happen
>>> to have a CPU board from one, but not the box itself.
>>> One of these days, I plan to burn "real" PDP-11 ROMs and bring 2.11BSD
>>> up on mine.  That and my Pro380 are my only KDJ11 machines.
>>> -ethan

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