It's been a hell of a day! HP 9845/2x i8008/Sage II/2x Grid/TI

[Christian R. Fandt]

Upon the date 16:45 15-05-05, Tony Duell said something like:
> >    Left there and went to see the guy that I'd meet that morning. He gave
> > me a ***MINT*** Visual 50 terminal, a MINT Sage II computer with ALL the
>
>I haev a Sage II (the later model with half-height 80 cylinder drives),
>and the _excellent_ owner's manual with full schematics in the back. What
>I don't have is an OS for it :-(. If anyone has the set of original disks
>that came with such a machine, I am looking for copies (IIRC it was the
>UCSD p-system, with some Sage-specific utilities).
>
> > docs, a working HP 9845B, a stack of manuals for the 9845, a couple of HP
>
>There's a 9845 in many bits on my bench at the moment. %deity it's a
>complicated machine.... I think I just about understand the buses now
>(and evne that's complicated -- there are 2 main buses, essentially
>'language' ROMs and memory on one, 'peripheral' ROMs and memory on the
>other (one ROM drawer is on each bus), both processors have access to

Tony, the HP250 CPU is said to be the same as the 9845* except for 
different microcode. Reference this website if you can: 
http://www.hp-eloquence.com/history/history.html

Anyway, a couple of lines of text in the description on that site states: 
"Technically a descant [sic, probably meant descendant] of the HP9845 
workstation it was targeted at the commercial market." and further went on 
to state: "The HP250 used a HP proprietary 16 bit processor (similar to the 
one used with the HP9845) supporting 192 Kb to 512 Kb of memory."

Now, to give some real meaning to this posting for you, refer to the set of 
schematics for the HP250 on bitsavers:

http://www.classiccmp.org/bitsavers/pdf/hp/250/45251-90001_HP250sch_Jun82.pdf

Problem is that this is a 14.5 meg file and I think you are still on a slow 
connection. Maybe somebody near you reading this could print it out for you 
or somehow get you the file on a CD-RW or something if you use Adobe 
Reader. Anyway, pages 74 and 75 show the board layout and schema, 
respectively. Whole document is 142 pgs.

I feel this may give you something to work with as you reverse engineer the 
9845. You didn't say, and I assume it to be very much the case given the 
lack of tech manuals for our own 9825 machines, that there was any tech 
manual (w/schemas) for the '45, hence my suggestion of this file to at 
least get something to help you along.

I've got an HP250/30 and I dang near passed out when I discovered this 
drawing set on bitsavers last year! About 15 years ago I even drew out the 
schematic of the CPU board and part of the HP-IB board just to learn 
something of the machine. I had been resigned to *never* find anything such 
as this during the past 20+ years I had the machine. Never say never, as 
they say . . .

Thanks VERY much to whomever scanned and uploaded that seemingly rare HP 
document!

Regards, Chris F.

NNNN


>both buses, the video system can access both buses via the peripheral
>processor's buffers, etc. Evne the PSU is about twice as complex as you'd
>expect!
>
>-tony

Christian Fandt,    Electronic/Electrical Historian
Jamestown, NY  USA      cfandt at netsync.net
         Member of Antique Wireless Association
         URL: http://www.antiquewireless.org/