I have a large collection of paper tapes that came with a vintage Altair
680b and Teletype model 33 that I inherited. I've restored the machines
and have started looking at the tapes. Unfortunately, I have discovered
that the rubber bands that were used to keep the tapes rolled up have
all dissolved into a yucky gooey mess that is in most cases, stuck to
the tapes.
I'm pretty sure the oil on the tapes and 30+ yrs time have done this dirty
deed. Sadly, there were original, unopened MITS Altair editor/assembler
tapes, BASIC, etc. still sealed in their original packaging but the
rubber bands inside have melted all over the tapes.
Has anyone dealt with this kind of cleanup before? What are my best
options for solvents to get rid of what's left of the rubber without
damaging the tapes too much more?
What a mess.
Parents, talk to your children about rubber bands...
Chris
--
Chris Elmquist
mailto:chrise at pobox.com
Hello,
Could someone help me understand the algorithm used
for data integrity check on ST251 MFM drive.
I have ST251 drive and an Adaptec controller. Also I
have ability to view recorded data in raw format.
On the track I see ID field block protected by CCITT
CRC16. And the data block protected by some 32-bit
ECC. This is definitely not a CRC32. The algorithm in
general looks like shift register for polynomial
multiplication with polynomial equal to
x32+x28+x26+x19+x17+x10+x6+x2+1 . But, this is not
just a multiplication. The circuit has some other
logic that I did not understand yet.
I?ve found very useful document
(http://www.national.com/an/AN/ AN-413.pdf) It has a
mention about algorithm called ?Glover 140A0443 ? May
be this is that I have?
Please advice.
Thank you.
Alexander.
>
>Subject: Re: vac tubes / was Re: Schematics of Atanasoff-Berry
> From: ard at p850ug1.demon.co.uk (Tony Duell)
> Date: Sat, 06 Sep 2008 21:34:08 +0100 (BST)
> To: cctalk at classiccmp.org
>
>> > I really don't understand this modern love with making things as
>> > small and light as possile. I'd rather have things that are heavy
>> > enough to stay put (in the case of a rack unit, not to topple, or
>> > even feel wobbly when units are extended ot the maintenance position)
>> > and that are large enough for me to be able to work on them.
>
>[For the record, I consider the OP's comment that he wants to use a PC
>PSU becuase he has one or that it's convenient, or.. to be entirely
>reasonable.]
>
>>
>> Bigger and heavier means less items in your collection to fit in the
>> space, and a smaller number before the floor falls out from underneath
>> of it. I'd hope you could appreciate that. :)
>
>So by that arguemnt we should all collect handhelds, not desktop and
>rack-mounted machines :-)
>
>> Another problem I seem to have is that the heavier an item is (and
>> harder it is to move myself), the less I seem to be able to find people
>> to help move it.
>
>Fortunately I don't mind having to dismantle something to move it. Many
>of my larger machines came into the house in small-ish pieces. I
>remember, for example, dismantling a DEC RA60 on the back of a friend's
>pick-up truck (fortunately the RA60 is dismantled from the top down, so
>this wasn't hard), taking the bits inside and then putting them back
>together.
>
>Gettign back to the OP's heater supply, I don't think a mains-input
>heater transformer to supply 5 normal-sized receiving valves is going to
>make the device impossile to lift. If you used ECC83s (12AX7s), I think
>you could use a 20VA transformer with no trouhle at all, and that's
>hardly large or heavy.
>
12AX7 at 12.6V @.15A (1.8VA) or parallel connected 6.3V @ .3a and I consider
that trivial. A transformer sufficient to run 10 of those (18VA) is under
2-3pounds. The average 12V at 1A wall wart can run six of those with a comfortable
margin. We are not talking a lot of power yet. If we are in the realm of 100
or 1000 of those then we have some power needs to deal with.. The solution
there would be to use instead of one 12.6V transformer that can give 150A we
can use ten more readily available transformers of a mere 15A (189VA) which
is more manageable anyway.
That same transformer (assume 12.6V AC) could using a voltage multiplier
easily supply 40-45V where the valves would have a decent usable performance.
This is easy as those valves at 40-50V will only need a few milliamps per
plate circuit.
I know this as I built a 5 tube reciever (6AN8, 6AU6, 6BH6, 6CW4, 6dl6/ECL84)
for 80/75M and the whole radio fits in a 7x8 chassis and with the power
transformer and audio output transformer is under 6 pounds. The transformer
used was salvage but had a 150V 100mA winding and a 6.3V 3A winding (total
of 34VA) and that was not even stressed hard and weighed on at under two pounds.
Another example is 40 years ago I had a Beckman EPUT (events per unit time)
counter that used the then typical tube era 5mhz ring counter decades with
neon readout (0-9 with NE2 type neon behind them) (6 ofthem) plus timebase
for a whopping 42 tubes mostly of the 12AX7 types and it was big (19" rack
width by 11" high) but I distinctly remember it as barely 40 pounds
considering it was fully enclosed in a steel case and each decade
was in its own case that plugged into a matching socket in the cabnet.
Powering tubes in that class (ECC83s) is trivial compared to the day of the
ABC where typical dual triode was maybe in the class of 6SN7 (6.3V at .6A) or
worse. Early tubes where power hungry for heater power.
Allison
>
>> I in no way said that I wanted everything made of lightweight (and
>> easily breakable) plastic, it's just annoying when things are severely
>> over-enginered and thus increase the weight, or use heavier components
>> when lighter ones would work in a perfectly acceptable manner.
>
>Well, there are limits, but I must admit I tend to admire solid
>overengineered devices.
>
>-tony
Hi,
I have had an email from an owner of an AES Plus system, who is looking to give it away to a good home.
This system is a dedicated Word Processor, built around an 8080 processor. The owner has loads of disks too, these might be rare 16-sector hard-sectored types and so it would be worth collecting the system just for the floppies.
If you are able to collect the whole system from the Toronto area, please email me and I will pass your details on.
Regards,
John
_________________________________________________________________
Make a mini you and download it into Windows Live Messenger
http://clk.atdmt.com/UKM/go/111354029/direct/01/
I've got a bunch of DIMMs pulled from RS/6000 SP hardware available for
not much cost. The memory is 3rd party (Kingston) 512MB DIMMs that
were used in Purdue's SP high node systems. Third-party memory doesn't
seem to be worth much, so I'm not asking too much, say $10+shipping per
set of 8 or so.
These are equivalent to IBM FRU 07L9758, F/C 4121 or 4100
This memory works in at least the following systems:
7044-170 (44P-170)
7044-270 (44P-270)
pSeries 640 / B80
pSeries 620
9076-270 thin/wide and 9076-N81 SP high nodes
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
heres a link to some lead solder
http://www.acehardware.com/product/index.jsp?productId=1290635&cp=2568443.2…
Chris
On 10/2/07, Zane H. Healy <healyzh at aracnet.com> wrote:
>
> At 11:37 PM +0100 10/1/07, Tony Duell wrote:
> >For the first part, I'd offer to do it for you, but it would be illegal
> >to do so. Owing to our totally daft laws, (a) I'd have to use lead-free
> >solder, which I don't have, don't trust, and am not set up to use and
>
> How hard is it to work with lead-free solder, and is it becoming a
> problem to get traditional solder in the US? I've been meaning to
> pick up a few rolls. As I'm still using a roll purchased in the 80's
> from Rat Shack for building a couple things for my VIC-20, I haven't
> been going through it that fast. Though I seem to be using it more
> often now than.
>
> >(b)
> >it has been said that if an enthusiast (specifically a model engineer,
> >but it would apply here too) does jobs for others, then his workshop
> >becomes a workplace and is covered by all the daft health-and-safety
> >rules that I have no desire to get involved with, and which quite
> >honestly, would stop me from getting on with things.
>
> Does it count as a job if you don't take payment?
>
> Zane
>
>
> --
> | Zane H. Healy | UNIX Systems Administrator |
> | healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
> | MONK::HEALYZH (DECnet) | Classic Computer Collector |
> +----------------------------------+----------------------------+
> | Empire of the Petal Throne and Traveller Role Playing, |
> | PDP-10 Emulation and Zane's Computer Museum. |
> | http://www.aracnet.com/~healyzh/ |
>
While reading comp.sys.cbm, I ran across this site:
http://simonowen.com/fdrawcmd/
I would imagine that this driver would come in quite handy for those
wanting to work with foreign formats while using Windows.
g.
--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
Hi folks,
I hope a Mac SE is old enough to chat about here - it's hardly newer
than my pdp11 or Vax!
Anyway, the Mac's good, but the flyback Transformer burnt out a while
back and I was wondering what would be a suitable replacement. I have
information on the Mac Plus analog circuitry from Mac Tech and the parts
numbers for the Mac SE flybacks. However, none of this gives me the spec
for the flyback and since AFAIK they're not available any more, I'm
wondering how to get a suitable replacement. It doesn't have to look the
same, it just has to work and be reliable!
http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html
Tai-Ho/Taiwan R.O.C. TH-1565C Mac SE
Lifon/Taiwan R.O.C. 157-0042-A Mac SE, Repaired analog board, SE/30
Lifon/Taiwan R.O.C. 157-0042-B Mac SE, Repaired analog board, SE/30
Lifon/Taiwan R.O.C. 157-0042-C Mac SE, Repaired analog board, SE/30
http://home.earthlink.net/~gamba2/images/plus_analog.PDF
This is probably going a bit far ;-) :
http://members.misty.com/don/samflyhv.html
-cheers from julz @P
Picked up a recent acquisition and thought I would try here before I send to
eBay. I have an original IMSAI 8080 in great condition. It comes with two
floppy drives. I don't really know how to test but it powers up and all the
blinking lights come on. Taking best offer of cash/trade. I'm located near
Seattle WA. Obviously if you're local trades will be easier. Email me with
offers.
