Hi all,
I'm trying again to get my 11/750 running. It turns on, power lights are green, machine comes up halted with the dim error light as it should. THe problem I am having is, I get no console...I get an echo back of the characters I type, but nothing else. Doing a BREAK command or a Ctrl-P does nothing.
The closest thing I can find to this problem is in the 11/50 FAQ, found here:
http://www.vaxarchive.org/hw/750faq.html
Here is what the FAQ states:
"Help! My machine isn't listening to the console!
Symptoms: machine starts up normally and prints the successful microverify double percent and the console prompt, but ignores console input.
This may be because the RS232 line receiver on the console port has given up the ghost. I've had to replace the one on mine twice. Note that it isn't a good idea to leave the console terminal switched on if the machine is switched off -- the line receiver chip doesn't like this and tends to fail eventually.
To replace the line receiver:
a) Locate and remove the L0004 UBI module.
b) Hold the UBI component-side up with the edge connectors down the RHS.
c) Locate E53, a 1489, at the right-hand side of the board, near the top of the second edge connector. This is the only 1489 on the board.
d) Replace E53. I strongly recommend using a socket for the replacement. "
Now, this does not sound similar to my problem. I have indeed verified that all the jumpers on the backplane are in the right place, and so are the connectors. The jumper is set to 300 baud, and that is indeed the only setting I get a clean echo back without garbage on.
Any suggestions? I'm out of ideas at this point.
Julian
Hi Al
I forgot to mention that the Technical manual
seems to be missing page 93. This is the same
as I have. It might be interesting to make a trip
to the Stanford library and see if they have
this page in their copy.
I'm not sure when I'd be able to do that.
Looking at the manual, there doesn't seem
to be any context missing but a single
page section could have been missed.
For non-students and non-graduates, one is
limited to 3 sessions a year at the special
collections section of the library. One still has to
reserve the document a few days in advance.
If you are interested in researching other
documents from Jef's collection or anything
else in there vast collection, I can point you
to their information.
I wonder if the CHM might already have some
special arrangement with the Standford library
on shared information for research purposes.
Jeff left quite a bit of stuff related to early
Apple days.
Dwight
On Thu, 04 Dec 2008 16:26:40 -0500, "Curt @ Atari Museum"
said:
> I've got a large box of TU-58's with boot up and diags
> for a Vax 11/750, any out there want to make archives
> of them or has that already been done?
Definitely want to help!!! I'm always looking out for
this kind of thing. My 11/750[1] came with a handful of
TU58 carts and I've still got the TU58 drive fixture
that I cobbled up to my PDP-11 to make images. I'd be
more than happy to image what you have.
I've located a few (maybe 10 or so) 11/750 diag cart
images in the past, but I'm still looking for that "full
set" of standard 11/750 diag tapes. If you have them
(or, even if not) I'm game for imaging what you've got.
I'm in Utah, so there's probably some shipping involved,
but I'd probably be able to cover charges both ways to
help with getting these imaged. How big is that "large
box" you've got? ;-)
- Jared
[1] After a year I'm still struggling with bringing my
11/750's 5V power supply back to life. Tony A., look
for me to come begging some help, probably after the
holidays.
>
I have no idea about the material, but I can tell you about one
application method you may not have considered. I have mentioned it
here before but maybe you have joined the list recently.
Similar drums were made by ICT/ICL from 1962 to 1965 for the 1300
series, and probably for the 1200 series drum based computers in the
50s.
They too had fixed heads with set screw adjustment, which was carried
out by monitoring the pressure of compressed air blown through a
venturi in each head while moving an Allen screw.
The 1300 drums were 12000 48bit word capacity, driven by a 3/4
horsepower motor geared up to 5240rpm at the drum spindle for lower
access times.
After many experiments they found they could not beat the human hand
applying a magnetisable compound like a potter making a pot. Sounds
very low tech but apparently it works, and I have drums which have not
been touched since manufacture and they still work 46 years on. Of
course for you, low tech could be a bonus as it means low cost. Maybe
your local educational establishment has a skilled potter who could do
a great job for a reasonable price, or just for interest.
> The drum is quite low density, and does not have air bearing heads.
> The head heights are actually adjustable with a bunch of set screws.
> The heads themselves are also pretty big. This is a late 1950s drum,
> not a 1970s era hard disk - there is a world of difference. I would
> bet the heads ride a few thousands above the surface.
>
> The whole assembly is in a very rigid cast chassis, driven by a
> relatively low-frills AC motor, apparently.
>
> My thinking is that the drum could be recoated (this is assuming it is
> indeed shot), and using the rigid cast chassis, ground down to a
> smooth surface with a custom made tool. This is much like a "poor mans
> wheel lathe" used on railroad wheels. As long as the bearings are
> still pretty tight, there should be very little wobble between the
> drum and chassis. With each head being adjustable for height, much
> inaccuracy across the drum becomes fairly unimportant. Inaccuracy
> around the drum is more of an issue, but I suspect it will not be too
> bad if the correct tool material and magnetic coating is used, and the
> drum ground down gently. I will ask my real machinist friends about
> the tooling, as I doubt I (or any of us) could make it.
what is this unit for? If that *someone* isn't interested in all 10, I could be, given someone tells me what it's for. I'm getting my hands on some SONY equipment and I'm a little nervous you see!
--- On Wed, 12/3/08, Kathy Galvin <kathy.galvin at advantageic.com> wrote:
> From: Kathy Galvin <kathy.galvin at advantageic.com>
> Subject: Sony MP-F52W-00D needed
> To: cctech at classiccmp.org
> Date: Wednesday, December 3, 2008, 2:32 PM
> Hello
>
> Did you find the drive you were looking for
>
> SONY MP-F52W-00D I have qty 10 of them.
>
> Make me a offer on all 10
>
>
>
> Email: Kathy at advantageic.com
>
> Phone: 978-568-0899 ask for Kathy
Does anyone know of a 'bridge' converter that would allow a scsi disk to interface to an MFM controller?
Michel Adam
----- Original Message -----
From: Dave McGuire <mcguire at neurotica.com>
Date: Wednesday, November 19, 2008 8:38 am
Subject: Re: AT&T 7300/3B1's (was: Re: Who is vintagecomputermuseum?)
> On Aug 18, 2008, at 10:26 AM, Mark Tapley wrote:
> > I'll hunt for mice. I don't think I kept a spare, but if I did,
> > I'll let you know.
>
> [old message referring to 3B1 mice, I couldn't find mine]
>
> I found my 3B1 mice. I hope to get the machine running soon,
> but
> I seem to have a shortage of functional MFM drives. Ugh.
>
> -Dave
>
> --
> Dave McGuire
> Port Charlotte, FL
>
>
>
The Qume DT8 I have has only the HL line cut on the programmable shunt
block at 1E. This doesn't match any configuration shown in the usage or
service manual.
Also, it has the SS trace (between U3E and U3D) cut. This trace is not
explained anywhere in the user or service manual except that it is shown
to exist.
The schematic at the end of the latest rev manual at bitsavers shows
that it has something to do with whether head 0 or head 1 is selected
(or perhaps loaded) in regards to the READY and INDEX signals on the
shugart interface. Does anyone know exactly what it is supposed to do? I
got lost in all the logic.
Thanks,
--
Jonathan Gevaryahu
jgevaryahu(@t)hotmail(d0t)com
jzg22(@t)drexel(d0t)edu
