HP 9845 Option ROMs

John Ball ball.of.john at gmail.com
Thu Jan 28 00:16:47 CST 2016

So in the past few weeks I've been playing with my latest aquisition, an HP
9845A that's been upgraded at some point to a 9845B. The filter caps for the
PSU are in the mail still and I have yet to actually see the system turn on
so I've been working on other projects in the meantime like cleaning the
machine, troubleshooting faults in the floppy drives it came with and
sourcing a food dehydrator to bake the tapes it unexpectedly came with.
It's a fairly basic machine without the internal printer or second tape
drive. Only the I/O, graphics and Mass Storage ROMs are installed and
there's at least one other option ROM module not accounted for according to
one of the manuals that came with. In fact it seems the option ROMs aren't
common to begin with or at least they are not cheap on ebay. I seem to
remember a few years ago someone out further West than I am who also had a
45 discussed some sort of ROM board that acted like the PRM-85 ROM board for
the HP 85 and let you load whatever ROMs you wanted onto a modern EPROM and
do away with HP's silly modules completely however my memory is fuzzy and I
can't seem to find any mention of such a device on the internet. What I did
find was the System ROM replacement board on hp9845.net but it doesn't
mention the ability to add in images of the option ROMs he has available on
his site. Anyone else heard of this mysterious adapter?


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