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.
The PX8 had suffered a minor burn-up in the PSU area, which I have cured
(one new transsitor, resistor and zener diode. The computer now seems to
work find (and it's a very nice toy).
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 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.
OK, a bit of background on the PF10 internals. There's a 6303X
microcontroller (in an 80 pin package...) linked to a 27C64 EPROM
(socketed) and a 6116 SRAM (SMD again). Address decoding is mainly done
by a '138, with a few other TTL chips.
Linked to that is a 765 disk controller, drivers for the head stepper
motor, a data seperator chip, read/write chain, etc (note, there is no
seperate logi board on the drive mechanism, the heads, stepper, etc plug
straight into the controller board).
There are several power supply lines, most of them under the control of
the microcontroller. In particular, there's an always-on 5V line, a
switcehd 5V Line (the disk controller, etc, is powered down when the unit
is idle), +/- supplies for the RS232 drivers, a +12V line for the
analogue circuitry.
OK, at power-on, the 'power' LED comes on (I have connected 5V from my
bench supply in place of the NiCd battery pack). The always-on 5V line is
at 4.95V. None of the othher supples are present (this could be right at
this point)
I connected it to the PX8, DIR D: gives 'BDOS ERROR ON D: SELECT'. A
breakout box connected between the computer and the drive (RS232 levels,
rememeber) shows that when I run that command, the computer's serial port
is turned on, something comes on on the TxD line, but the disk drive
never turns on its port or sends anything back.
More worrying, reducing the voltage from by bench supply never turns on
the low battery LED on the drive unit. This is controlled by the
microcontroller, BTW.
I pulled it apart, of course. The serial data from the PX8 does get to
the appropriate pin on the microcontroller. The microcontroller is
clocking (1.23MHz on the Eclk pin), it's accessing the ROM, but it also
appears to be wandering around the memory map (outputs on the '138
decoder that are not used for anything are being asserted at times). The
address lines look odd to me, with pulses narrower than the Eclk on some
of them.
Since the ROM is socketed, I pulled it and read it out. It looks sane.
Certainly no data bit is stuck high or stuck low, and all the address
lines do something. Assuming it's like a 68xx processor, with reset and
interrupt vectors at the top of memory, that looks sane too.
I suspect the microocontroller or the RAM. Alas both are SMD (and
therefore a pain to remove), I have spares for neither and no way to get
them.
Any comments, suggestions, or things to check?
(Yes, I know about PC-based emulators for these drives, but I'd like to
get the real unit working too).
-tony
I have NetBSD 2.1 running on my minibox (sort of- curses isn't working and I haven't gotten around to troubleshooting it yet). I was asking because DSL isn't available here, which makes getting the software a bit difficult, otherwise I'd try it out.
Hi,
I know a few folks here own HP 1600-series logic analysers, so I hope this
isn't stretching the boundaries of on-topicness too much..
I've just hacked together a little symbol loader for the 1651B. All it does
is read a text file full of "LABEL = $F00D" format lines, then loads them all
into the 1651B's symbol table. Very handy when debugging microprocessor
systems with one of these analysers (especially when you've got an inverse
assembler for the target CPU).
In addition to that, I've also thrown together a 6502 inverse assembler for
the 1651B (though it *should* work on the other 1650 and 16500 series
machines too). It understands all the Western Design Center 65C02S "extra"
instructions, and should (in theory at least) work with raw 6502 and Rockwell
65C02 code as well.
Oh, and it calculates the actual target of relative addresses, too. And
cross-references addresses against the analyser's symbol table (see above) :)
Now for the icing on the cake - I've also written an inverse assembler
downloader. The old IALDOWN util that HP released with the Inverse Assembler
Toolkit won't work on anything faster than a PC/AT (IIRC), so I grabbed a
copy of the 1650B Programmer's Manual and threw together a Windows-based
(although it could be ported to Linux console-mode easily enough) tool to
replace IALDOWN.
OK, so the million dollar question is, should I clean up the code for these
apps and release them? Does anyone else use one of these analysers, or am I
the only person on the planet who considers a 1651B to be "good enough"?
Has anyone else written any little tools or analyser addons like these?
What about inverse assemblers?
I've seen the 8008 disassembler Jim Kearney wrote, but that seems to be about
it...
Licence will probably be a BSD derivative - along the lines of "Use it as
much as you like and for whatever you want as long as you credit me in
whatever you derive from it, and change the name of your app."
IALDown32 was written with Delphi 3, the symbol table uploader was written
in ANSI C using mingw32 (read: GCC with a Win32 twist).
Thanks.
--
Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT
philpem at philpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook
... James Dean taught Marc Bolan to drive.
>
>Subject: Re: OT: "Best" Linux Distro?
> From: "Chuck Guzis" <cclist at sydex.com>
> Date: Thu, 01 Dec 2005 09:46:04 -0800
> To: cctalk at classiccmp.org
>
>Others have observed the bloat in Linux and I agree. I started running it
>on an 8MB 386 and it was pretty snappy. I don't think that feat could be
>reproduced with any of the current distros.
>
>Cheers,
>Chuck
Same here. There are a few that barely run on anything less than p-III
class hardware.
Since I have an abundance of older 486class stuff I use Freebsd 2.2.6
and a 7 year old copy of Slackware or Caldera OpenlinuxV2.3 when I
want a linux box.
Allison
> You can turn it off with the little switch inside the main batter
> compartment. The machine should run from the main battery
> (or a 5V PSU connected in place of the main battey) if there
> are no otehr problems.
Both of my PX-8s (an earlier and a later model) will run with the 6V
wall wart connected into the proper socket when the main and wedge
batteries are removed. I wouldn't exactly recommend bypassing the
little bit of protection the charger input provides.
Josef
--
"I laugh because I dare not cry. This is a crazy world
and the only way to enjoy it is to treat it as a joke."
-- Hilda "Sharpie" Burroughs,
"The Number of the Beast" by Robert A. Heinlein
I have a pair of Pertec-branded circuit boards,
14" x 16"x, marked as follows:
PE WRITE
PC86V1
101387-01K
101388J
PE READ
101389-01J1
101383H1
I was told that they came from a tape drive.
They are primarily populated with 7400-series
TTL, with date codes around early 1976. Each
has a small daughterboard, 2.5" x 3", with
discrete components -- I would imagine these
would be the analog circuits for read/write.
Does anyone recognize what drive these boards
come from? I don't have any particular need
for them, so if anyone has a drive that could
use them, I'd be willing to part with them
easily.
--Bill
I have four of these to get rid of. They are used and
wired, and most have bypass capacitors soldered in on the
component side, but the wiring side is wire-wrap only.
These aren't the greatest boards, and I doubt that unwrapping
them is any fun, which is why I culled them from the lot that
I bought. They are available for the cost of postage, however,
or free for local pickup in Santa Clara, if anyone is interested
in them before they go to the scrapper.
--Bill
>From: "Richard A. Cini" <rcini at optonline.net>
>All:
>
> Just a quickie.what would be a suitable replacement for the opaque
>labels that one would stick over EPROM windows? I was going to use
>electrical tape but it's so sticky and white mailing lables leave glue
>residue.
>
>Rich
>
Hi Rich
Unlike disk write protects that need to block infrared,
ultra violet is blocked by most anything. I like to use
the white self sticking labels found at most stationary
stores. These are easy to write on to indicate rev and
other information. I've also taken scissors to the
main labels for floppies and cut them into small enough
strips to cover the windows.
One can also get laser printer labels as well.
It is true that over time the glue will dry and be hard
to remove but googon (or similar) works well.
Dwight
All:
I'm thinking of ditching Windows totally on my desktop at home
as I build my next upgraded x86-bsed PC. So, I wanted to take a poll of the
group for a recommendation on which Linux distro to use. I downloaded Fedora
Core, Slackware, FreeBSD, Unbuntu and Linspire.
Any thoughts from the group?
Rich
