5 Jan
2007
5 Jan
'07
6:38 p.m.
Rather than just 'plug' a resistor into the back of the PSU, I like to get
the
regular cable to the battery backup box, and use that.
Its a common cable, I may have spares.
I pull the lead acid cells out of the battery boxes, and leave the stock
thermistor
in place.
The advantage is that with the battery box in place (or even a blank rear
plate)
the airflow through the I/O cage is much better than when the back plate is
missing.
The same thing is true for the blank plate over the memory card cage. Early
memory controllers will run much hotter without this plate in place.
HP put these parts there for a reason it seems. My I/O slots are packed, so
I try to keep them happy.
Having lots of DMS memory can be a real advantage. I've got software that
gives
you up to 32 separate address spaces, so you can jump between totally
incompatible
programs on a single machine. This allows an IPL program to run HP Basic,
and
then return control back to the original IPL code, etc.
Swapping the system map around is great fun!
----- Original Message -----
From: "Glen Slick" <glen.slick at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Friday, January 05, 2007 6:34 PM
Subject: Re: HP HP-2117F on ebay
On 1/5/07, Jay West <jwest at classiccmp.org>
wrote:
I'd yank all those 64K cards and just run
with one 256kw board, keeping
the
2nd 256kw board for spare. All those "little" 64k boards just suck up
power
and don't give you much extra memory. I generally don't run things that
would require more than a pittance of ram anyways.... so others here will
certainly disagree with me on this point.
Extra RAM is always good for making the self-test count higher on the
blinkenlights. :-)
I just recognized the "unknown" board
at the top in slot 25, it's a PSI
(Programmable Serial Interface) board (built on a 5180-1953). I think
that's
a 3rd party board. I would like more info on these boards if anyone has
it.
Sketchy info follows that may only be half-accurate: There are four
Z80's?
on board as I recall, and 3 proms to dump your z80 code in to.
That sounded similar to what I remembered about the 12792 8-Channel
Mux, but I just looked at the manual and it has a single Z80, DMA,
CTC, 4 SIO/2s, and 16K of DRAM. I wonder if there is anything
interesting you could do with those with your own firmware.
Warren... I'll gladly trade some of my HP
boards in exchange for one or
two
of the microcircuit boards in there ;)
I have a few 12566 boards and some relay boards, forget their number.
I have looked for those 9 pin power supply
connectors
too, to no avail :( I'd love to find some of the new crimp pins at
least!!
AMP doesn't seem to remember making them.
I'd like to make a real plug for the battery backup 820ohm thermistor
bypass. I just have a resistor with its legs folded over wedged into
the connector for now.
-Glen