On Jun 4, 0:52, Tony Duell wrote:
[useful stuff]
> But not everyone has an EHT meter. It's probably OK to use a 10M resistor
> (prefereably a high-voltage one) and a well-insulated screwdriver to
> discharge the CRT. Connect one end of the resistor (use clip leads, etc)
> to the CRT earth and the other one to the screwdriver blade. Then push
> the screwdriver under the edge of the anode cap and hold it in contact
> with the metal contact for about 30s.
Most resistors are rated for a 500V or 1kV rather than EHT, so there is a
small risk that they'll break down or flash over. Better to use two or
more in series if you can.
It's also worth pointing out that even 1mA at 15kV is a fair wattage --
another reason to use more than one resistor. A large colour CRT might
have a 25kV supply. Of course, as Tony points out, usually the CRT will
discharge when switched off. But if it doesn't, that's just when you don't
want to find out the limitations of ordinary resistors. (I once proved
this theory on a Commodore PET).
Perhaps this is a good place to mention the "hand in pocket" rule: if
you're working on a high-voltage system, and one hand is in your pocket, it
can't be touching a good earth (unless you're even odder than I am :-)) so
there's a reduced chance of current crossing your body. You used to often
see TV engineers with one hand in a pocket and an EHT probe in the other.
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
>>From the yk2 Newsletter <http://www.y2knews.com/>:
>
>"The federal government is in dire need of technical resources to fix the
>Year 2000 problem-so dire, in fact, that there is speculation about a
>possible draft of Cobol programmers."
What, we don't have time to fix the Y2K problem but we _do_ have time to
build a whole new bureaucracy to mobilize the nation? Of course, the new
draft agency would have to be Y2K compliant so they can track down and
punish draft dodgers...
I guess it wouldn't do any good to skip off to Canada because _they'd_
probably draft you, too.
Roger Ivie
ivie(a)cc.usu.edu
At 15:41 6/3/98 -0400, you wrote:
>Everyone on this list predates the PC, except for maybe that Seagraves
>punk.
And Tim Hotze, Max Eskin.... anybody else?
__________________________________________
Kip Crosby engine(a)chac.org
http://www.chac.org/index.html
Computer History Association of California
<OK, logically I can send the bootstrap for the RL02 drive over the seria
<line since I'm running TELIX on a 486 for a console at the moment. The
<problem is the /73 doesn't support RL02's, and I'm getting tired of typin
<in all those numbers. Therefore the question is, how should I format th
<file that I send to the PDP-11? I've tried formating it two different wa
<and all I get is garbage sent to the PDP-11. I'm sending as straight ASC
11/73 does support RL02, I know I have one connected. When the /73
come up if the switches are set tight it will either boot straight away
or prompt for a boot.
If you send a formatted file it must look exactly like what you type right
down to the LFs (without CRs). If you aare typing it in to a file to send
likely CRs are being added where you dont want them.
Allison
A friend of mine collects and restores old reel to reel tape drives.
He recently showed me an Ampex 1080 (I'll have to double-check this
model number) audio recorder capable of 3 3/4 minutes of recording
time. Interestingly, this recorder uses a magnetic oxide covered mylar
floppy disk of about 12" diameter which doesn't have a sleeve by the
way (this disk puts the flop in floppy- it is extremely limp). Of
course this is serial access and analog, but could IBM had been
inspired by this unit? The recorder was a flop (pun intended)
commercially. The operation and service manual are copyrighted 1965
and 1967. I looked for patent material on the original IBM floppy at
their patent server as advertised on the list but didn't come up with
anything on the first IBM floppy drive. Any info would be greatly
apppreciated.
Marty
Well, I finally got around to picking up a Nicolet computer that's been
waiting for me at California State University Sacramento for the better
part of a year. Along the way a heap of HP stuff was added to the pile,
and I ended up having a whole trailer full of rackmount gear, racks, punch
card readers, disk packs, paper tape, and more.
Since I'm sure not many of you have ever heard of Nicolet Instrument
Corporation (Madison, Wisconsin), I'll tell you what I know so far. The
NIC-1080 is a 20-bit computer circa 1972. It has an assembler and a BASIC
via paper tape programs. I haven't determined how much memory it has yet,
although the computer has core in it, and I got a second Extended Memory
Unit (a separate box).
When it was decommissioned a couple years back it was still fully
functional. The computer is integrated into a big console with an o-scope
display and a plotter. This machine used to be connected to a magnetic
resonance imaging unit weighing several tons that was thankfully hauled
away by scrappers last year. It has special circuitry for doing fast
fourier transforms. It came with a Diablo 5meg removeable hard drive in
a separate rack, along with a Decitek paper tape reader (serial
interface). The computer has a serial interface, and a TI Silent 700 came
along with it, which was the primary console.
I also got a couple big boxes filled to the brim with paper tape software.
Nicolet formed a "Nicolet User's Society" whereby user's could submit
programs, and so there is plenty of public domain software on
punched-tape.
I also got a complete set of spare boards for the computer. The spares
came out of another Nicolet which was dismantled. The other Nicolet came
>from the China Lake Naval testing facility in the Mojave Desert so I'm
sure it performed some interesting calculations in its day.
Its a pretty fascinating machine. Its about the size of an upright piano
and weighs around 300 pounds. If you want to know more about it just ask.
If anyone wants to see pictures I can post them to the Vintage Computer
Festival web page.
I also got a whole pile of cool HP stuff, including a 9830B Calculator
with a whole bevy of peripherals, a couple punch card readers, a printer,
plotter.
Here's a complete list of the haul:
Nicolet 1080 Computer
NIC 1080E Extended Memory Unit (core memory)
Decitek Paper Tape Reader
NIC Disc Memory Coupler
Diablo Systems Inc. Series 30 Disk Drive (7 disk packs)
TI Silent 700 (thermal paper terminal)
Complete Nicolet paper tape library (over 100 different paper tapes
including debuggers, assemblers, BASIC, misc. programs)
Complete set of spare boards for Nicolet
HP 9830B Calculator
Complete manual set
About 20 program cassettes
ROM Packs
FP-78 Batch BASIC (Infotek Systems)
Ext. I/O ROM Eliminator (Infotek Systems)
FP-96 Data Communications I (Infotek Systems)
11273B Mass Memory
Mass Memory II (Infotek Systems)
Infotek Systems FD-30A Mass Memory (8-inch drive for 9830, stacks on top
of 9830)
HP 9866A Printer (stacks on top of FD-30A)
HP 9862A Calculator Plotter
HP 9869A Calculator Card Reader
HP 2761A Optical Mark Reader
HP 9868A I/O Expander
PS. I committed the stupidest mistake any computer collector could. I
totally forgot about the disk pack loaded into the hard drive. I never
checked to make sure the heads were locked. In my defense, I couldn't
remove the pack because the unit won't let the drive door be opened
without power. Does anyone know about the Diablo Series 30 and what the
proper procedure would be for locking the heads? Is the disk pack in
their most likely messed up now?
Sam Alternate e-mail: dastar(a)siconic.com
-------------------------------------------------------------------------------
Ever onward.
September 26 & 27...Vintage Computer Festival 2
See http://www.siconic.com/vcf for details!
[Last web page update: 05/30/98]
I might be interested, but it's in the UK. Anyone else?
>I am trying to sell a Superbrain and associated software.
>
>I am trying uk.adverts. computer but wondered if anyone could suggest
>anywhere else.
>
>Vic Lilley
>vlilley(a)netcomuk.co.uk
-Bill Richman
bill_r(a)inetnebr.com
http://incolor.inetnebr.com/bill_r
(Home of the COSMAC Elf Simulator!)
I have the following Atari stuff for sale for the best offer.
Atari DOS 3 manual
Atari TV switch box
Atari game paddles, 2
Atari 800 XL
Atari Claim Jumper Game Cartridge in a neat red transparent case
Atari book by Wiley Press, Atari BASIC XL edition
Email your offers and questions privately.
Joe
For sale, trade, whatever...
manney(a)lrbcg.com
TI-99/4A, adapter, RF Modulator
2 Joysticks
Cassette Player
Speech Synthesis Module (Broken case, rattles when shaken)
Dust Cover
CARTRIDGES
Household Budget Management
Hunt the Wumpus
The Attack
Chisolm Trail
Moon Mine
TI Invaders
Munch Man
Parsec
Football
Blasto
Adventure
Video Chess
Return to Pirate's Isle
TAPES
Pirate Adventure (Tape)
Books --
The Official Scott Adams Adventure Hint Book
User's Reference Guide
Beginner's Basic
Quick Reference Guide
Instruction book addenda
TI 99/4A User's Guide (Casciato/Horsfall)
TI 99/4A Game Programs (Holtz)
Untitled instruction book for some sort of flight simulator (Winging It?)
Anyway, What's a 68010 do? Anyone have pinouts/assembler refrences/etc?
Can I make it do something interesting?
-------
IIRC it has the same pinout as a regular 68000. The difference is in
how it handles page faults from the external MMU. On the original 68000
an instruction could not be restarted if there was a memory error (i.e.
it referenced a non-existent real address). The 68010 could restart,
which meant it could use true virtual memory, providing there was an MMU
to help things along (I think it was the 68450 MMU, then the 68550 PMMU
?).
I think there was a slight difference in the instruction set too. The
atomic instructions for semaphores were flagged somehow so the OS would
know to generate an error instead of an instruction restart (look up p/v
semaphores if you are curious as to why atomic instructions cannot be
restarted).
Jack Peacock
