On Thursday 22 December 2005 05:55 pm, Tony Duell wrote:
I am currently working on an Epson PX8 system. I
bought this on E-bay, so
the history is essentially unknown, but I was told it was 'untested'
which I took to mean non-working.
Speaking of which, I have one of those I'd forgotten to include in my list I
posted a while back. It used to work, doesn't work any more -- when I
attempt to turn it on I get a low battery message, even if it's been plugged
in to charge for a long time. Know where I might find some tech info on the
innards of the thing?
There is a scanned technical manual (.pdf) on various web sites, I think
it is on bitsavers, for example. Be warned that while it does contain
schemaitcs, these are very hard to read (at least the complete one at the
back) -- a combination of IMHO too low a reslution at one point in the
process (no idea if it was the original manual or the scanner) and a very
confusing layout.
There are part diagrams to explain the various sections, and these are a
lot easier to follow. THe PSU is not at all simple (and depends on the
NiCd to act as a shut regulator on the main logic supply line). Heck,
there's even a 4-bit microcontroller and a 6 bit ADC in the middle of it
all.
But I can try to talk you through it if you want me to.
<...>
With it, I got a PF10 floppy drive. This is a
single 3.5" unit, with a
38400 baud serial interdace back to the PX8.
I'd love to find a drive for one of those. :-)
It's not the same, but there are various drive emulators for PCs. The
'serial' port on the PX8 is at RS232 levels, and the disk drive just uses
the TxD and RxD pins (it's a subset of the pinout of the RS232 port
alongside it, you can use the same cables, essentially). It runs at 38400
baud.
I've downloaded a disk emulator for linux. The makefile and shell scripts
need work (at least to run on my machine), but the program compiled OK by
hand and does work. I think there's something for MS-DOS too.
I had to make up my own cable, but I have checked
and double-checked it, and
anyway it works fine to link a PX8 to a PX4 via the RS232 interfaces
(essentially the same pinout as the 'high speed' serial interface to the
disk drive). In fact what I did was make up a cable from the 8 pin nini-DIN
plug to fit the PX8 to a DB25 plug,, wired as a DTE and a second cable with
a DB25 socket to a 8 pin mini-DIN, wired to do the right swaps and jumpers.
I got a couple of connectors a while back, but my eyesight isn't what it used
to be, so I never did make up any cables. Do you have specific cable wiring
info, assuming I can get this thing working?
I regard mini-DIN plugs as one of the offspring of Satan :-). I really
hate wiring them, and the type you can wire (as opposed to moulded ones)
are often too large tor fit through the hole in the case to mate with the
socket.
What I did was buy 3 cables from RS components which had an 8 pin
mini-DIN plug moulded on one end and bare wires at the other. I wired 2
of them to DB25 plugs, so that you got a DTE pinout on said plug. And the
last one I wired to a DB25 socket with the apporpiate crosses and
interconnections so that when I pluged that one one of the first type of
cable, I got a crossover mini-DIN to mini-DIN cable which will like 2
PX8s (or PX4s), or link a machine to the PF10.
I can look up the wiring colours used in those RS cables if you like, they
are in the catalogue/on the web site, but I buzzed them out anyway just
to be sure.
[Note for US readers. RS is not Radio Shack. It's a large UK distributer
of electronic components, tools, materials, etc. Look at
http://www.rswww.com/]
First I've heard of those. If I can get mine
working, that would be a nice
way to store some data. What pc-based platform do they work under?
Well, certianly an old version of linux,, because that what I use. I
think I saw reference to an MS-DOS one. A google search for Epson PX8
and/or Epson PF10 should find them.
-tony