Wishing all here a very Happy New Year!
Along with some other folks in 2017 I have decided I am going to ripple
through all of my vintage systems and warm their beautiful and friendly
caches.
I won't have a problem with my BBC Micro, Atari 1040ST, Amiga 500's, 2000's,
3000 and 4000 and the PowerMac's but what I really would like is to bring my
Cromemco back on line. I have the cards (DPU, 256KZ, 16FDC plus sundry
others e.g. Quadart, IOP) and drives (Tandon TM100 5" and dual TM848 8") but
although I have a naked Blitz Bus I lack a decent chassis. This is a plea
for any kind soul with a spare or unwanted chassis who is prepared to let
one go to help me out. Ideally a CS/3 chassis would be preferable however a
Z2D, Z2 or even a System 1 chassis would be gratefully given a loving and
permanent home.
Naturally, given the weight of same, I expect I would have to pick up or
arrange transport so regretfully any offers would have to be UK-based. The
CS/3, and the Z2/Z2D had power supplies designed to handle a fully loaded
bus of 21 S-100 cards (although I never handled one with more than 12 or so)
and were one of those rare systems which could pass Navy certification i.e.
survive being stood on by a rating in full gear and boots so were quite
substantial.
I would also be very interested in a 64FDC and any 5Mb or 20Mb IMI drives as
I have a WDI-II controller, alternatively an STDC controller.
James
----
James Attfield
West Midlands, UK
G8ZMP
In a message dated 1/3/2017 11:11:54 A.M. US Mountain Standard Time,
elson at pico-systems.com writes:
On 01/03/2017 10:58 AM, Cory Heisterkamp wrote:
> While waiting for the machine, I decided to investigate the stuck drum.
> This unit has 71 read/write heads plus what appears to be an inductive
> pickup for the system clock. Upon closer examination I discovered
multiple
> heads in contact with the drum surface preventing rotation. And in the
> process of removing the mounting bars that secure the heads only then did
> damage become visible on a couple of tracks (scored oxide under the
heads).
Most likely the same issue as the G-15 we had. Dust was
allowed to get into the drum area and pack under the heads.
Probably if you pull the heads and clean them, it will
restore clearance. Of course, the bearings may be bad, or
will have to be replaced anyway as the grease may have hardened.
>
>
> What I?m wondering is if anyone is familiar with the setup/adjustment
> procedure for getting the heads set correctly. There *might* be a couple
of
> unused tracks I can relocate heads to, but my thought is that if half a
> dozen heads were already in contact, then the rest may be perilously
close
> as well (swelled drum?). My odds of setting 71 heads perfectly on a 50
year
> old worn drum is?well?not great.
>
If the drum can be set up to run true again (may need
attention to bearings) then I think setting the heads up
won't be that tough. I suspect it is done with a feeler
gauge, this is low-resolution stuff with large gaps in the
heads, so the heads probably run with a gap of at least
.005" (~ 0.1mm) (I'd think, without actually knowing).
>
> For kicks, I tried to use a piece of cheap (=thin) (0.004?) notebook
paper
> as a feeler gage to see if I could identify the offending heads prior to
> support removal. This was a no-go as clearance was too tight. So, is it
> true these ride 0.001? off the surface?
Well, it could be. That sounds really close for the vintage
involved. So, maybe the drum or oxide has swelled. Anyway,
if there is much damage to the oxide, it may not make sense
to try to repair it. if the heads that jammed it left
divots in the drum, or the surface is uneven (likely if
swelling actually occurred) then it may require extreme
efforts to repair.
>
> I suspect with temp and humidity changes, and given the age, I would be
> better off building a solid state drum emulator for the 4KW mem, but
> retaining the drum for the clock and possibly the 3 fast registers..if I
> can get those (7) heads set correctly.
>
>
>
>
Why not just replace the whole works? If you are going to
replace the long lines with electronic memory, doing the
short lines and the clock track should be trivial. I think
a mid-sized FPGA could do it all quite easily.
My guess is that if the surface is uneven, it may not read
back data reliably. The high spots might be fine, the low
spots will have dropouts. This is all assuming swelling was
the culprit.
It is also possible that machined parts suffered stress
relief over the years. Wrought metal has stress imparted to
it when rolled, and then machining will partially relieve
the stresses, causing warpage. The warping continues over
time. To eliminate this, critical parts are machined close
to size, heat treated to relieve the stress, and then finish
ground to exact dimensions. It is possible some of the
stress wasn't relieved during manufacture.
And, nobody expected a 195x machine to be running in 2017,
especially as anybody in the computer business knew those
transistors were right around the corner, and would almost
certainly replace tubes.
Jon
Cory - then what holds the oxide to the drum? Horrible thoughts of what
happens to binder layers on mag tape... flaking, sticky shed....
ecccshhh!
I deal with this problem all the time on some of the historic video
tape we have done conversion on out of our media lab.....
Hi,
On Mon, Jan 02, 2017 at 10:32:28PM -0800, Richard Pope wrote:
> Walter,
> . . . . I appreciate all of this information. I have a revision 2.0
> board and my info shows U8 as a 96S02 multivibrator chip. I have tried
> to find a replacement for this and I have not been successful.
I believe this is a suitable replacement. I found it while getting the
parts together necessary to build my bare IA-1010 Z-80 board.
"AM26S02PC - Schottky Monostable Multivibrator ( 5 pcs ) - 16 Pin DIP Plastic"
http://www.ebay.com/itm/261370092245
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
Pics of what I'm trying to find at
http://www.retrocomputing.net/parts/compugraphic/mcs_keyb/
Bought one w/o kb or monitor and managed to locate a few floppies for it. CP/M 86 was available from CG, but
I don't think there's much chance of ever finding that.
Even just a dump of the microcontroller in the kb would be helpful. I'm not quite sure who the contact
would be at retrocomputing.net to ask if they could dump the one in theirs.
I have the PALs dumped and disassembled, will have those up on bitsavers later this morning.
Sorry for posting the National machine w/o an Ebay warning.
Anyway anyone that has a home keypunch will possibly be interested in
this guy.
I have ordered up a pile, as I doubt they will show up this cheap unless
someone takes it on themselves to manufacture them as the earlier
discussions suggested. Not holding my breath for that.
I don't personally care that there is a lot of crap printed on them,
rather than the column indexes. The machines don't read that, and the
top band is clear for my keypunches to write there with whatever is on
the card.
thanks
Jim
Has cases of 2000 and also cases of 5 x 2000 = 10000 cards (look for the
5 case auction separately)
http://www.ebay.com/itm/272488557055
Hi all --
Thought I'd share this fix with you all just in case someone in the
future might make use of it.
Long story short: Got myself a CMD 710/M UNIBUS SCSI controller with
the intent to use it in my VAX-11/750, running 4.3BSD-Quasijarus.
Unfortunately it won't boot (it hangs shortly after "loading boot" is
printed to the console). VMS boots, NetBSD > 1.6 or so boots, Ultrix
boots, but no luck with 4.3BSD.
I spent some time adding some debug spew to the bootstrap (on SIMH) and
testing (on the 750), and the hang is inside udcmd() in
sys/vaxstand/uda.c. I then stumbled on this usenet post:
https://groups.google.com/forum/#!msg/alt.sys.pdp11/61LZNTo9Dgg/Q6dI9om_LIEJ
Which indicates a similar problem with a Viking controller on a
different 4.3BSD variant. The code in Quasijarus is a bit different,
but the cause is the same.
The fix is:
Change line 155 of sys/vaxstand/uda.c from:
if(u->uda_ca.ca_rspint ==0)
to:
if(u->uda_ca.ca_rspdc & MSCP_OWN)
Rebuild, and re-run disklabel to replace the bootstrap.
Hope that helps someone else someday...
- Josh
On Thu, 12/29/16, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
> Interesting factoid about the Bendix G-15: it was designed with the help of
> one of the ACE people (Harry Huskey), and is basically a re-packaged ACE with
> drum instead of delay lines. There's an interesting article by Huskey himself
> in "Alan Turing's ACE" (by Jack Copeland) which discusses the G-15.
Indeed. Huskey is probably one of the most influential, least known
early pioneers. He was one of the engineers on the ENIAC, having
designed the card reader and punch interface units. He spent some
time at NPL and was one of the prime pushers behind the idea of
building a pilot version of the ACE. When he returned to the US, he
designed both the SWAC and the G-15. Later he was on the
faculty at UC Berkeley where three of his advisees were Niklaus
Wirth, Ken Thompson, and Butler Lampson. And he turned 100
early in 2016.
BLS
In a message dated 1/3/2017 1:09:50 A.M. US Mountain Standard Time,
jwsmail at jwsss.com writes:
On 1/2/2017 11:26 PM, Brad H wrote:
> I brought the RFI thing up with him. No response. There is a legit Rev
1 there too asking $3500. I don't find Apple IIs below Rev 0 that
interesting anymore, personally. I think even the legit guy would struggle to get
much above $1500.
The vintagecomputer museum guy on epay is selling mounted and framed
motherboards now for $1500 (might not work noted).
I guess someone would care about low ref Apple 2's but I'm not sure why
there would be any interest. I've got one I bought with the original
packing box, which I have picked and moved twice, which is rare for my
collecting, but I don't know what makes any Apple 2 like that
collectible. As in why are they collectible with low serials / part
numbers.
is there any documentation as to when they were made with those numbers
that would make them significant? The numbers made as Raymond said
would make most of us with Apple 2's millionaires I'd think unless they
have some other significance.
just curious.
thanks
Jim
Jim the vintagecomputer museum guy wants a crazy price for a roll of
teletype punch tape...
I do not understand some of his prices. Ed#
