Re: HP9826/36 PowerFail option RTC?

Dave McGuire

On 1/8/20 1:10 PM, rmb_guru via Groups.Io wrote:
We had a HP9826 setup with the Powerfail option on the HP8566 production
line.  It worked very well in keeping the HP9826 running during AC
blackouts and to allow the hpl software to have a controlled shutdown of
the system at the appropriate time, when the blackout continued almost
beyond the battery capacity.

NOTE: The HP9826 we had ran 24/7 for over 100,000 hours (11+ years)
along with a HP9134A 5MB Hard Disk, with a minimal amount of shutdowns
along the way due to power-outages and/or maintenance.  The HP9826 was
the data server in a HPIB based network that we used to connect all the
HP8566 Test stations together, running hpl.  I still have the HP9134A
and it still runs fine even after 30+ years.  Its internal 5 MB Hard
Disk was built by the HP Disk Memory division and it is built like a tank.

If memory serves, you would see the Powerfail option listed in the
hardware portion of the HP9826 boot screen.  But that is the extent of
the "BIOS" knowing anything about it.  The individual language (i.e. hpl
and HPBASIC) had the knowledge/commands on how to use the Powerfail option.

The option consisted of installing a battery/board/module into the
bottom of the HP9826 / HP9836.  I've attached an image showing the panel
on the bottom of these computers where the hardware would be  installed.

I've attached an excerpt from the Hpl operating/programming manual,
which talks a bit about the option and how to use it.
I have the installation manual for the option and probably HPBASIC usage
info as well, but I will need to dig around for the paper copies.
An interesting option. I have one of these in one of my 9826s. It
made quite a mess when the batteries went, but I'm pretty sure I can get
it cleaned up ok.


Dave McGuire, AK4HZ
New Kensington, PA

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