I picked up Eric's DP 1500 Z80 system at VCF West this weekend, unfortunately
the boot disk has bad sectors. Anyone have any diskettes/images around for the
1500 or any other version of their systems?
I took pics and dumped the firmware from it along with a DP 1551 pcb I've had
for a while, and have been uploading the manuals to bitsavers that came with it,
as well as a bunch that I've had scanned in the backlog
> I didn't fully disassamble the program
I have now done so; the -YK is _exactly_ the same as the -YA (the later ones,
which are minorly different from what's in the manual), except that the HSR
address (177550) has been replaced as the primary device address by that of
DL11 #1, in the second block of DL11 addresses (175610).
In other words, the ROM is prepared to load something in bootstrap loader
format (which I have documented here:
http://gunkies.org/wiki/PDP-11_Bootstrap_Loader
the one program known in this format is the absolute loader) over the
non-console serial line.
Noel
Hi list,
Just came across this:
https://www.ebay.com/itm/Vintage-Computing-CDC-Magnetic-Peripherals-Control…
Haven't seen one listed in years. The price lets me assume that this offer addresses customers that may use these drives in a production environment or so...
I am not aware of museums or hobbyists who have such drives currently in a functional state to read and write from and to 80MB (CDC 9762) or 300MB (CDC 9766) disk packs. Maybe the CHM? ... not taking into consideration the CHM activities related to the Xerox disk cartidge? (2315-equivalent) software archive project.
Anybody out there? Would be interesting to know.
Best regards,
Pierre
-----------------------------------------------------------------------------
http://www.digitalheritage.de
I'm looking for a full set of manuals for the Microsoft Professional
Development System v7.1. If anyone here has them to loan for scanning or
to sell, please contact me directly.
Thanks!
g.
--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby. Geeks collect hobbies.
ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!
After replacing the RAM, the display is now back to normal (there's also a
test switch on the motherboard (S6) that switches the display from blank
spaces to all zeroes.
The one that failed was a National Semi 2102, whereas the others are all
>from another manufacturer. No sign of previous replacement. Interesting.
(I once fixed up a PDP-8/L, chased down several bad chips. Nearly all were
Signetics 7440's).
I may have made a tactical error though - turns out that wet/damp PVA is
electrically conductive! Enough to overcome the 5k pullup resistors. An
unpleasant surprise. So now the keyboard thinks multiple keys are being
pressed and won't work at all. Removing the keyboard to clean underneath it
would be very tedious since every key has two soldered pins...
There was a significant buildup of goop underneath the key scan mux and
demux chips where the pins are close together (0.1"). I gave the bottom half
of the board another good
rinse and will let it dry overnight, maybe a hair dryer too. Or get some
more 91% alcohol to it and a longer low-temp bake. It all worked before my
"cleanup" so I expect it will resume normal operation once the moisture is
out of any remaining goop. I hope ;)
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The DEC VT20 terminal apparently included a PDP-11/05 with a direct mapped
character display and was intended for text editing and typesetting. It
seems to have been followed by the VT21, and then VT71/VT72, all three based
on an LSI-11 (KD11-F). There's a real lack of documentation about these
online, although the VT72 does have a print set.
Apparently the VT20 used the M792-YK as its bootstrap; the Field Guide is
silent regarding the boot device and M792 documentation stops earlier in the
series of variants.
According to the VT72 print set, it used the MRV11-VC (M9942-YC; described
in the Field Guide as a "bootstrap/diagnostic module") for its bootstrap but
is also silent regarding the boot device. In interestingly, the Field Guide
also describes a MRV11-AA (M7942-TB) as a "M7942 with VT52 emulator, VT71
bootstrap".
For async. communications the VT20 used a DL11-B (M7800 (EIA)). the VT72 a
DLV11-F (M8028).
Looking in a DEC "Options and Modules" listing I see VT20 bundles including
Typeset-11 and DECset-11, and it appears that the VT20 could be configured
with two displays & serial lines in a single 11/05.
So . is the boot device in these systems the remote host via the serial
line? What protocol would that have been? Something native to Typeset-11
and DECset-11?
paul
Thanks Bill, I hadn?t seen that particular page. As I mentioned already, the
formerly clear ?stuff? was so deteriorated I could just pull the glass plate
off with gentle fingertip pressure.
I ran a bead of clear silicone around the outside of the clean plate and CRT
face and bonded them back together.
Display looks great!
However, I can now see that every other line, starting with line 2, is
showing a full line of double quotes (0x22) instead of spaces (0x20). I read
the circuit description and schematic, and it appears that bit ?2? is stuck
high on the even-line RAM ? for some reason the designer decided to call the
LSB bit 1 instead of bit 0.
Typing (for example) ?abcdef123? shows the correct text on the blank odd
lines, but on the even lines it echoes as ?cbcfef323?. Confirming that stuck
bit.
Looks like the RAM at location H15 should be the bad one... we?re having a
heat wave and it?s too hot upstairs to work on it until tomorrow morning at
the earliest.
ETA: Now it's tomorrow morning and just cool enough (although 100% humidity,
at least outside) but my replies aren't showing up in the archive - filtered
somehow.
Anyway. I did a bit more Googling and discovered that plain water dissolves
the PVA goop just fine. No need to use a lot of expensive alcohol which
seems to be a less effective solvent anyway!
So I took the board out and scrubbed it in the kitchen sink with running
warm water and an old toothbrush. Rinse with distilled water, now gently
baking in the oven at around 140F to get the water out of the keyboard. Then
onto the RAM replacement.
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I have access to 3 ES45s, a DS15, and an RA8000 in a tall blue Compaq rack
in Athabasca, Alberta. All the in-service disks were removed but all the
spares are available. The box also has the fibre switches used the connect
the RA8000 to the servers and the cables, much of the paper documentation,
and assorted doodads. It would probably work if plugged in but it has been
a year since it was turned off.
Athabasca, Alberta is about 1.000km North of the US Montana border and
10,000km from nowhere but it is summer and the weather is nice so we might
be able to load this great heavy beast on a trailer and haul it up to a
day's drive away if anybody want this stuff. This is rural Alberta so
a day's drive is a l-o-n-g way (like 1,000km?).
I tried to give this away in early 2019 but the deal fell through. If
I don't get a place to send it then I will keep the DS15 and convert the
rest of it into scrap metal.
--
Richard Loken VE6BSV : "...underneath those tuques we wear,
Athabasca, Alberta Canada : our heads are naked!"
** rlloken at telus.net ** : - Arthur Black
Testing 1,2,3... my last couple of posts don't seem to be showing up?
-Charles
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