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On Thu, Feb 14, 2013 1:37 PM PST Tom Gardner wrote:
>Let's not be US centric - I nominate AMSTRAD for one of the worst designed
>system boxes. The cables basically blocked all airflow resulting in all
>sorts of thermal problems, and the data separator, designed by some UK
>consultants who knew nothing about the subject, limit-cycled eating up all
>the disk drive margin.
>
>Tom
Didn't Acorn dabble in pcs? What about Research Machines? Fairly robust, no?
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On Thu, Feb 14, 2013 2:44 PM PST Tony Duell wrote:
>If you don't wantto etch your own PCB, it's relatively hard to get a male
>card edge conenctor
you can accomplish rudimentary masking and etching by using cheap packing tape. Encapsulate the board then slice and remove portions of the board you'd like to etch away. No copper sulfate IIRC (the etchant) won't eat your fingers. Just DON'T pour it down the drain, protect your clothes and be careful of animals.
(and if you do etch your own board, it's non-trivial
>to gold plate it).
Well plating can be accomplished in the home shop but where are you going to get the gold. Wait for a meteorite?
But it brings up an interesting idea of mine. Couldn't you reverse plate the gold right off of pins and whatnot? No nasty chemicals, no mess, no fuss.
it is, however, quite easy to get header plugs of
>various sizes, including ones with wire-wrap pins.
>
>If I ahd to make such an adapter in a hurry (== no time to make the
>PCB)_, I'd probably put 34 pin and 50 pin wire-wrap headers ont a bit of
>square pad board, wire-wrap approrpraity, and fit one of said adapterso
>nto the 34 pin header to conenct to the edge connector on the cable.
If I'm following you, couldn't you cut the card edge from a busted drive, solder that to an appropriate board (I would have to assume the spacing is identical), solder a header connector, preferably right angle, to the opposite side of the board, then solder jumper wires where appropriate?
Hi all,
my Name is Alex, me and a friend of mine have been actively
participating in a computer collection, mostly repairing
stuff and bringing it back to life. We have numerous old apples, vaxes,
decstations, suns, next etc and some
real weird old stuff ;)
Lately we discovered a DG nova standing in a dark corner of a storeroom.
We have absolutely no peripherals, just
the bare machine. It has 2 CPU boards, a general IO card, 2 Memory
boards and some unknown third party controller.
The Machine as it sits now has 2-3 problems (at least):
1: Somehow the "desposit next" switch does not work as expected by not
incrementing the adress sometimes. Doing a deposit-examine next-deposit
works, so thats a minor problem.
2: Simple programs run fine in single step mode. Press RUN and the
machine seems to hang. You can not even STOP anymore, you have
to reset the machine. Annonying, but to test the simple stuff single
stepping also works....
3: The biggest problem is: The ACs have numerous bits stuck on 1. It is
the same bit pattern for all ACs. We can store and
deposit the non-stuck bits, but all others remain a 1. With this
behaviour its really really hard to write any meaningful asm to
test the machine ;)
Please see the attached Link for pictures of the machine and the
bit-pattern of the AC. Since the AC Deposit works as expected
and the error shows only when examining we are positive that the error
is not in the AC Registers itself but somewhere where
the switch location is actually shifted into the AC....or something like
that. We are also struggling a bit to get all the documentation
in a meaningful relation. So if you have any pointers on what to do or
check, please chime in.
If the machine gets back to life i have plans on emulating a storage
device to run one of the available os-es. Should be doable with
a microcontroller and some logic glue.....but it looks like a long way ;)
See actual pictures of the machine here
http://bigalpha.ath.cx/nova/pics/ori/index.html
where you can also see the bit Pattern of the AC.
I kinda wonder why its
1 11X 111 X11 1X1 11X
I guess this should point us nearer to the point of failure.
best regards
Alex
I just joined the group, although I have had a long time appreciation of vintage computing technology. I spent most of my career on the software, marketing and most other aspects of computers but not hardware. I have put together systems, hacked at things, but at a light level, until recently. I decided to really learn how to design and engineer, choosing a project that would expose me to many aspects and be a forcing function for developing quite a few skills. Not that this makes me a full bore EE or able to design at a current technology professional level, but enough so I could envision, design and make hobby items of pretty much any scope I wanted. The project is a replica of an IBM 1130, a low end mainframe contemporaneous with S/360 and sharing the same logic and other technology. My aim is to build one that is an experiential replica - one that brings me as close as I can get to the experiences and behavior I had sitting in front of the console hand stepping through code back at the end of the 1960s. The internals are based on modern FPGA but producing a cycle by cycle accurate system, faithful to the timing on the real machine. I have a blog detailing the work, my current state and goals, if anyone is interested, at ibm1130.blogspot.com
Currently I am adapting an IBM Electronic Typewriter model 50 - a late model of the Selectrics - to serve as the console printer since the 1130 used a 1053 (Selectric based printer). The keyboard is being adapted from a keypunch keyboard, since the 1130 used the keyboard from an IBM 029 punch, and even where I am using more modern devices (a streaming link over USB to a PC to present card images to the peripheral adapter logic, I have made it timing and behavior faithful. The processor itself is working quite well, which is why I have moved the focus to peripherals. It is a very similar effort to that of Lawrence Wilkinson who has built a 360 model 30 and is also building peripherals at this time. You can read about the 360/30 project at http://www.ljw.me.uk/ibm360/vhdl/
I am hoping that members of this group will be able to share advice and information as I look to adapt something like an RK-05 disk drive, since it is very similar to the IBM 1130 drive, in a later phase. It is a truly quixotic project with no clear end, but will give me the excuse to dabble in all manner of old technology along the way. Hopefully many of you will have fascinating projects and experiences that I can enjoy.
Carl
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Hi Folks,
I just heard that the Spare Time Gizmos SBC6120 partial kit is being offered as a Kickstarter project:
http://www.kickstarter.com/projects/sparetimegizmos/classic-pdp8-replica
There are just 12-days left until the project expires. It currently has 11 of 30 slots filled.
Only 30-slots are available and all must be filled for the project to be funded.
I have signed up for one, so I'm hoping that it goes forward!
Steve L.
>From what I've read kickstarter also requires some formal example of a finished product now as well. Not just a pipedream with sponsorship. I imagine they're trying to use that as some security vs pay for an idea that someone might not be able to produce.
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On Thu, Feb 14, 2013 3:35 PM PST Chris Long wrote:
>Research Machines made a whole range of PCs starting with the first Nimbus.
>
>I have one in the collection but have had little time to look at it tbh.
I used to have a Nimbus mobo.
And I was thinking Apricot, yet said Acorn (that made a pc).
I seem to recall using a PCjr drive (Qume?) to image disks in a newer pc..
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On Thu, Feb 14, 2013 3:20 PM PST TeoZ wrote:
even the floppy drives were different then anything on a clone because the power was in the data cable).
I have a 3B2/1000 that I'm trying to resurrect. The main Winchester drive is dead-ish (haven't written it off, but it's doing spinup-click-spindown so there's something big wrong), so I need to label a new drive.
3B2s are DSQD floppies, and I'm trying to figure out my best approach. I have the utility software in a disk image, but PCs usually don't ship with DSQD drives. I've found three possible options, but don't know if anyone's used any of them (or one that I haven't come across).
(1) Mount the 3B2's DSQD floppy in a PC and try to write out the disk using it. Don't know if the PC's disk controller supports DSQD- I have a Compaq Deskpro 386/25 and a whitebox Pentium that I can try
(2) modify one of the above machine's stock 1.2MB drives to spin at 300RPM. Don't know if it will write out the disk this way, but found mod. instructions here: http://www.oldskool.org/disk2fdi/525HDMOD.htm . May work, may not -I'm not sure how QD and HD head widths compare.
(3) Replace the 3B2's 5.25 DSQD drive with a 3.5" drive and use 720K 3.5" disks to load it. Don't know how well 3B2 hardware would like this mod.
I do have the proper DSDD media to use, so that's not an issue. I'd probably write the disk out with "dd" on Linux or xBSD if possble, as the network support makes getting the image to the writing machine much easier.
Anyone been in this position before?
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On Wed, Feb 13, 2013 1:35 PM PST Cindy Croxton Electronics Plus wrote:
>I have seen plenty of 8-bit and 16-bit floppy controllers where the end
>drops lower than the connectors, especially if the card is very long; it
>supports the card in the case or the motherboard. Usually there is a brand
>of some sort. Sorry, I can't identify it by the numbers you gave. Maybe if
>you could post a pic somewhere of the front and back?
I know I have. Can't recall off the top what computers used them or if they were just early ISA cards. But remember this seems to be an oldee. Or was it just populated (repopulated?) with old chips? Otherwise what could be that old and mostly look like an ISA card? What bus used 62 pins?
