New find, Edax PDP 11/23 system available.
bshannon at tiac.net
Fri Jan 5 19:40:09 CST 2007
I've just found an interesting vintage system.
The machine is an Edax 9100 / 70. It contains a PDP 11/23 with MMU and FPP
running RT 11 V4, circa 1980.
The Edax 9100 is a rather odd beast. Its a system that attached to a
scanning electron microscope
and used a cryogenic silicon sensor to measure the spectra of emissions from
the microscopes target
and calculated the elemental composition of the sample.
This system consists of three main sections. Each section connects with
fairly long sets of cables, so
each section is designed to be seperated, built onto or into an existing
scanning electron microscope.
There is the main chassis, a very mice short roll-around 19-inch rack with a
formica top. This holds
the 11/23 minicomputer in a custom backplane. There are a number of Q-bus
slots, and a large
section of custom backplane holding some fancy custom ADC modules and a
video display and
The Q-bus section holds the following boards
M8186 KDF11 (revision unknown, probably an early one)
M8044 DE (memory)
M8028 (no idea)
A Sigma Floppy Disk Controller (RX02 emulation? boots as DY:)
A Dialog ST-506 disk controller
M8016 YB (don't know this one either, I used to drive UNIBUS 11's)
A DEC 4 SLU board, no M# on the handles.
There is a Shugart 8-inch FDD, complete with the original shipping cardboard
to protect the heads.
There is a ST-506 drive in the chassis somewhere, I don't know the capacity,
or if this is a 8 or
5.25 inch drive.
There are a number of power supplies for the electronics, as well as a high
voltage supply for the
special silicon sensor that was attached to the SEM. I don't have the
sensor, its still being used on
the SEM with a newer EDAX controller box.
Keyboard / Console unit:
A very retro-looking, nice keyboard with extra function keys, and a row of
display modules for programmable legends over the function keys. All
apparently controlled by
standard RS-232 links to the 11/23. The displays look like old Litronix
According to the documentation, the standard keyboard section is used to
boot the RT-11 O/S.
The EDAX application was driven by using the special function keys and
programmable key legends
on the LED displays. One function key dumps you back to the RT-11SJ prompt.
Video Display unit:
Uses a portrait-format CRT in a (then) futuristic tilt-swivel metal chassis.
This interfaces to the
special video display system in the main chassis. This monitor would be
placed next to the normal
display graphics of the scanning electron microscope and would display the
spectra of the sample
being tested along with text displays of the settings, elemental
This same display is also used to talk to the PDP/11, I'm thinking that the
UART in the display
section (I have full schematics) is used to emulate a dumb terminal with the
section on the Keyboard / Console unit.
This thing ran RT-11 SJ V4, and uses a modified version of DEC's basic.
Users could write programs
in BASIC and CALL functions that ran all the analog front end and display
systems. Custom analysis
programs could be written and saved to disk. A sort of batch mode would run
factory and user written
programs to study and test samples.
There is whatever is on the disk, and the original factory 8-inch floppys.
There is even the original Dialog DSD ST-506 disk controller utility and
diagnostic disk with the
Dialog D7026A formatting program.
This thing has been removed from service, and has been sitting in the room
next to a working electron
microscope in a top notch analysis lab since its been delivered from the
factory in 1980 or thereabouts.
Its never been moved, or stored in a non climate controlled space. The
condition is excellent.
There are full service schematics and some documentation of the software
(like all the calls to run
the front end and display stuff). The I/O addresses for the custom hardware
appear to be well
The roll-around rack is quite short, maybe just under 3 feet high. With the
display and keyboard sections
the whole thing is a bit smaller than an Apollo DN660, but very similar in
I do not have the (Hubble twist lock) power cable, and I've not tried to
powe the thing up.
This thing is in Massachusettes.
Right now this thing is sitting in my office at work with scrap paperwork.
There is a paperwork
process I need to go through to take it out of the building, but I suspect
that the disposal fees the
company would have to pay are such that they would be very happy for me to
remove this thing
for them (free to me).
Moving the thing (during the winter) will be a small pain however.
It will fit into the back of a Jeep Wrangler with the back seat removed, so
I can get this thing home
but I cannot place it into heated storage. I can store it in my garage, but
I'll have to rodent proof
the thing (but it will be stored next to my Lotus).
The little roll-around rack is very nice, so I have to admit I might part
this thing out. So if someone
really wants the Q-bus boards and the floppy and hard disks out of it, lets
talk. Better still, if someone
wants a little RT-11 box, and does not care if the DEC logo is nowhere to be
found, this might be
a fun and funky little box to hack around on.
Its really got killer retro looks, the styling of the thing is really
something (photos are possible).
The keyboard / console section appears to have a standard serial interface,
and its a very cool
keyboard, nice feel, very vintage. That could be easily hacked onto
whatever vintage machine you
As for the CRT display, given that its got a portrait oriented tube,
probably uses some totally strange
video format that is nearly useless without the Edax display hardware.
Oh yes, there is a high voltage inhibit switch, so you can switch off the
1,000 volt bias supply to the
sensor head if your just using the computer. A nice service feature thats
essential if someone wants to
keep this thing intact and use it as a conventional 11/23 box (but full the
fuse for the HV section, just in
case someone turns that switch back on, you don't want 1 kV hanging off the
end of a disconnected
Trade offers are welcome,
I'd love to have either a working printing terminal (like a LA34) or just a
printer that can take green
bar paper. Serial or parallel interface will do.
Oh yes, if chopped up, parts can be shipped. If you want the whole thing
you need to come and
pick it up in MA.
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