>From: "Kevin Handy" <kth(a)srv.net>
>
>Geoffrey Thomas wrote:
>
>>>This is more of what I'm getting at. Does it matter that some knowledge
>>>is lost as generations go on? Are we ever going to need to go back to
>>>tubes to design electronic circuits?
>>>
>>>
>>>
>>There was an idea some time back that if we ever get to the moon that we
>>could be using "open-air" valves (tubes) in the vacuum there for high
>>powered devices - with the benefit that goes with the better radiation
>>resistance that goes with valve technology.It would be quite cool to watch a
>>tv picture on an open CRT methinks.But don't walk between the plates.
>>Keep those old Mullard/Thorn/EMI books - GE in the states?
>>
>>
>I think you would have problems with cross-talk between the
>open tubes, unless you limited your design to a single tube,
>or had large spaces between the tubes.
>
>The glass does more than just hold the vacuum, it is also an
>insulator.
>
>
Hi
Just some wire mesh that is charged can make a shield.
You just have to herd these pesky little electrons.
Dwight
Just a mention that when it was looking like DEC was gone from the flea
markets, This month there was a VT-180 Robin, which I snared, and a
Rainbow w/Harddrive and upright stand, which I left ffor the next lucky
customer. Also a lot of interesting Mac and Sun, some Atari game
machines. Great overall.
OT: PC/Pentium400's are at the $10 point now, which I take as a greenlight
to toss some of the more boring (yes,PC's) of the like or just less so that
I've saved.
The next MIT flea is the day after the VCFe, so I may lose out on a few
deals to some other lucky collector that month.
John A.
/edit
I've got a 3com EtherLink III MCA card available if anyone wants it. It
failed to sell on ebay, so just cover postage costs (plus paypal fees if
you pay me that way) and its yours.
Anyone want it? If you want to view it, see below:
<http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5704862265&ssPageName=A
D
ME:B:EOAS:US:3>
the ad lists as $3.85 for shipping via Priority Mail. That is my prefered
method to ship things like this, because I get free boxes. If you want
some other method or are out of the USA and can't use that method, I'm
open to changing it.
If I don't get a taker, its heading to the trash... so hopefully someone
will want it. (I no longer have any MCA bus hardware, so it is useless to
me)
-chris
<http://www.mythtech.net>
David -
A great site for old test equipment is
<http://www.logsa.army.mil/etms/find_etm.cfm>. If the US Military had
it as a standard piece of equipment they will have the manuals on-line.
Both TM 11-6625-2735-14-1 and TM 11-6625-2735-24P-1 are on line and
cover the Tek 475. Good luck gathering the smoke...
Claude
> ------------------------------
>
> Message: 26
> Date: Fri, 18 Jun 2004 11:32:39 -0400
> From: "David V. Corbin" <dvcorbin(a)optonline.net>
> Subject: OT : Tektronix 475A Scope...
> To: "'General Discussion: On-Topic and Off-Topic Posts'"
> <cctalk(a)classiccmp.org>
> Message-ID:
> <!~!
> UENERkVCMDkAAQACAAAAAAAAAAAAAAAAABgAAAAAAAAAC6RJHIx+0kSwesJ7EUMCZcKAAAA
> QAAAAZViPZir1Wkad3T578gnBuQEAAAAA(a)optonline.net>
>
> Content-Type: text/plain; charset=us-ascii
>
>
> Does anyone have a set of schematics or docs? Mine just let all the
> magic
> smoke out. Visual inspection looks like a cap let go, but I would like
> to
> make some measurements [having to use a voltmeter] before I blindly
> replace
> the obviously fried cap.
>
> Please reply to me off list david(a)dynamicconcepts.us.
>
>From: "der Mouse" <mouse(a)rodents.montreal.qc.ca>
>
>> There was an idea some time back that if we ever get to the moon that
>> we could be using "open-air" valves (tubes) in the vacuum there for
>> high powered devices
>
>Is the "open-air" vacuum on the Moon a hard enough vacuum for
>vacuum-tube technology? Does it depend on whether it's day or night
>(and therefore whether there is solar wind pouring in)? I know that
>_some_ vacuum-tube technology - notably CRTs - depends on electrons
>having a mean free path well over the tube size, and that needs a
>pretty hard vacuum.
Hi
Even with all the solar wind, the surface of the moon has
a much harder vacuum than any of the tubes we have on Earth.
The moon does have a problem for such devices. That problem
is dust. It could be blocked with filters but that is another issue.
>
>> - with the benefit that goes with the better radiation resistance
>> that goes with valve technology.
>
>Is it valves that give you rad-hardening, or size? A transistor the
>size of a valve would, I suspect, be inherently pretty rad-hardened.
>(Certainly the largest transistors I've seen are far smaller than the
>smallest valve I've seen. Probably by about an order of magnitude,
>once you strip each one down to the operating portion.)
There are still problems. A transistor can avalanche and not recover
without removing the power. A tube can recover with the power on,
as long as the metal don't ionize. So, it isn't just a size issue,
it is a materials issue.
>
>> It would be quite cool to watch a tv picture on an open CRT methinks.
It would take less energy since much is lost by the thickness of the
Phosphor.
Dwight
>
>Possibly, though it would mean either suiting up or building the screen
>into a wall. :-(
>
>/~\ The ASCII der Mouse
>\ / Ribbon Campaign
> X Against HTML mouse(a)rodents.montreal.qc.ca
>/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
>
here is some info for lacing...
http://www.hq.nasa.gov/office/codeq/87394-9.pdf
it shows some of the stitches, etc at least. It doesn't show a board layout though.
best regards, Steve Thatcher
-----Original Message-----
From: Gene Buckle <geneb(a)deltasoft.com>
Sent: Jun 21, 2004 10:06 AM
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk(a)classiccmp.org>
Subject: RE: Modern Electronics (was Re: List charter mods & headcount... ; -))
> Were these true harnesses or were they cable assemblies. The difference
> being that a true harness is completely assembled prior to installation
> [usually on a board] where a cabble assembly is the use of lacing (or other
> methods) to "dress" simple cables [Simple in the respect that they are
> usually point to point [2 connectors] or have few branches]?
>
Does anyone have pictures of how these kind of frames were built? I'm
going to have to build at least two of them soon for my simulator project.
I plan on lacing the wiring harnesses that run down the side consoles
since it looks so much nicer than dozens of wire-ties.
> Did you use spot stitch, running stitches, or locking stitches? I can still
> do a decent spot or running stitch, but struggle with getting a decent [even
> spacing, high tension, low torsion] stitch.
>
Is there a tutorial anywhere that illustrates these various stitches and
where/why they are to be used?
tnx!
g.
>From: "David V. Corbin" <dvcorbin(a)optonline.net>
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1247&item=5103745074&
>rd=1
>
>Pobably the most complete system I have seen being made available....
>
>
Hi
It is also an early system. Most newer systems don't come with the
Digital Systems drives. This is one of the rarer DMA type setups
with the controller made from TTL. I would love to get a copy of the
Digital Systems manual. I'll be watching this one to see who
wins it. Maybe they won't mind making a copy of the manual for
me.
When I got my IMSAI, it had this drive system. I had to figure out
the floppy controller by figuring out the PROMs used in the state
machine. I wrote my own BIOS for it as well. It was a lot of work.
It wasn't until a few years later that I found someone else with
one of these controllers and actually got an original BIOS. It
was almost identical with mine ( no big surprise ).
I still use my IMSAI because it is handy to do my 8080 assembly
on ( and more fun ).
Dwight
Hello list,
I've been recently offered a Pro350 unit, depending on whether I can get past my budget and the wife. :-)
Said unit has 256kB RAM and a 10MB disk, presumably a RD51. No operating system. 4 SLU async card. VR201 monochrome monitor. F-11 CPU (LSI-11/23).
Some questions I have:
1. What OS can I run on this system? (Yes, I've heard the nightmares of the Piece of S* O/S). I was thinking in lines of RT-11...if so possible, then where can I get RT-11 for the Pro350? Is RSX-11 available for the Pro350?
2. Correct me if I'm wrong: Since it's the F-11 CPU, then it'll be limited to 18-bit addressing, therefore maximum RAM supported is 256kB, right?
3. Can I "upgrade" the RD51 with a RD54? Perhaps that depends of the bootROM and O/S support, right?
Thanks.
/wai-sun
--
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