HP 9810A and 9820A for sale Brisbane Australia

tony duell ard at p850ug1.demon.co.uk
Tue May 17 07:24:47 CDT 2016

> All complete and in good cosmetic condition except as noted.
> Assume that they all need repairs.

These are interesting bit-serial 'calculators' built from TTL (mostly).  I have
put 'calculators' in quotes because the internal architecture is that of a 
computer -- a processor that runs programs from ROM or RAM.

The HP9810 is a 3-register sort-of RPN machine, similar (at the user level)
to the HP9100. It has a 3-line LED display. The HP9820 uses normal 
infix notation and has a 16 character alphanumeric display.

Be warned that repairing them is 'fun'. A logic analyser is IMHO essential.
I am happy to talk about any aspects of these machines apart from the 
later (2102-based) RAM in the HP9820, which IIRC is what Opt 001 was.
I have never seen this.

> HP 9810A with options 001, 003, 004 and Mathematics and Printer Alpha ROMs 
> - small chunk broken off corner of front top cover

I assume 'front top cover' is the plastic bezel around the keyboard/display window.
This goes very brittle with age and it is rare to find one that is perfect. And if you do, 
it will probably get damaged if you work on the machine...

> HP 9820A with option 001 and Mathematics ROM
> Another HP 9820A with option 001 - very small chip broken off corner of front
> top cover
> I also have a spare card cage with backplane and four boards.

The separate cardcage in these machines is the memory unit. I wonder if this is the
original memory unit (RAM and control boards) from a 9820 that was upgraded to
Opt 001. From what I remember that upgrade was a replacement memory box,
controller boards and RAM boards, but you moved the ROM boards from the 
original memory unit.

> Open to offers.. Local pickup only, from Brisbane Australia.

Pity you are on the other side of the world.... (and anyway I have a 9810 and 9820)


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