Re: HP 7970B Capstan?

[Chuck Guzis via cctalk]

On 09/06/2017 08:14 PM, Al Kossow via cctalk wrote:
> I could mail you a skew tape.
> 
> On 9/6/17 8:09 PM, Chuck Guzis via cctalk wrote:
> 
>> I'm just scratching around looking for ideas.


If you could spare it for a week or so, I'd be grateful.  On the other
hand, my MCU setup for the drive works great--it reads a tape and
stashes the data as a .TAP file on an SD card.  At the same time, the SD
card appears as a USB storage device, so you don't need to remove it
from the MCU to read it.   Interaction is done via a serial connection.

Thanks,
Chuck

Re: HP 7970B Capstan?

[Al Kossow via cctalk]

I could mail you a skew tape.

On 9/6/17 8:09 PM, Chuck Guzis via cctalk wrote:

> I'm just scratching around looking for ideas.

Re: HP 7970B Capstan?

[Chuck Guzis via cctalk]

On 09/06/2017 06:50 PM, Jon Elson wrote:
> On 09/06/2017 12:11 PM, Chuck Guzis via cctalk wrote:
>> Will do--I've mentioned in another message that I'm preparing a test
>> tape using the drive, so I should get some inkling of timing and
>> adjustments pretty quickly. --Chuck 
> While that is good, an all-ones test tape made on ANOTHER drive that is
> known to be in good calibration (both speed and skew) is very helpful in
> standardizing drives.

Here's a thought--can skew be adjusted by writing,a block of data in a
forward direction, then reading it in reverse?  And then writing in
reverse and reading in the forward direction?   Ideally, when all is
right with the world, there will be no difference in the skew.

I'm just scratching around looking for ideas.

--Chuck

Re: HP 7970B Capstan?

[Chuck Guzis via cctalk]

On 09/06/2017 06:50 PM, Jon Elson wrote:
> On 09/06/2017 12:11 PM, Chuck Guzis via cctalk wrote:
>> Will do--I've mentioned in another message that I'm preparing a test
>> tape using the drive, so I should get some inkling of timing and
>> adjustments pretty quickly. --Chuck 
> While that is good, an all-ones test tape made on ANOTHER drive that is
> known to be in good calibration (both speed and skew) is very helpful in
> standardizing drives.

I realize that, but I don't have another NRZI known-good drive to
calibrate against.  PE and GCR, sure, but not NRZI.   I'll have to rely
on luck for skew adjustment.  I can probably work off the tach signal
for speed.

--Chuck

Re: determing date on TI 99/4 computers.

[Sam O'nella via cctalk]

http://www.computinghistory.org.uk/det/1344/Texas-Instruments-TI-99-4A/ has 
interesting knowledge of the serial for dating. 
I don't know if it was my newb brain/false memory but i thought I saw someone 
post a ti-99/2 prototype before (vcfed search can probably prove me right or 
wrong). But the models really were already stated as the 99/4 being the first 
and noticeable from chicklet keyboard and orange?/red keys on the bottom 
corners.
Then i think they had an expansion system that my memory gets confused with the 
trs-80. 
I didn't realize it was a 16-bit system though. That's intriguing and worth 
some more reading to see what it did vs the competition.
 Original message From: John Wilson via cctalk 
 Date: 9/6/17  1:57 PM  (GMT-06:00) To: william degnan 
via cctech  Subject: Re: determing date on TI 99/4 
computers. 
On Wed, Sep 06, 2017 at 02:07:22PM -0400, william degnan via cctech wrote:
>I'd double check that.   I have found, at least in my experience, that the
>beige are more plentiful than what you'd expect if they only made them for
>a few months.  I bet they were made for the last year or more of the run.

Is it possible to retrofit the beige keyboard?  I remember Radio Shack was
dumping surplus beige TI-99/4A keyboards super cheap for a while there, so
I was wondering if maybe people could've used them as repair parts?

Also, was there ever a TI-99, TI-99/2, TI-99/3 etc.?

The Bill Cosby TV ads were kind of embarrassing in retrospect ... but they
were funny at the time.  He didn't seem like much of a computer nerd.

John Wilson
D Bit

Re: HP 7970B Capstan?

[Jon Elson via cctalk]

On 09/06/2017 12:11 PM, Chuck Guzis via cctalk wrote:
Will do--I've mentioned in another message that I'm 
preparing a test tape using the drive, so I should get 
some inkling of timing and adjustments pretty quickly. 
--Chuck 
While that is good, an all-ones test tape made on ANOTHER 
drive that is known to be in good calibration (both speed 
and skew) is very helpful in standardizing drives.


Jon

Re: Xerox Alto Chordset Pictures (was RE: VCF?)

[Curious Marc via cctalk]

Steve,
Now that you see the shape in detail, feel free to ask for the specific 
dimensions you'll need as you go along. I'll take the caliper out and make 
precise measurements.
Marc

On Sep 6, 2017, at 1:00 AM, Steve Malikoff via cctalk  
wrote:

>> Steve,
>> 
>> Here you go, 13 pictures of the Chordset. That's about as orthoscopic as I 
>> could get them.
>> https://www.dropbox.com/sh/owjnyvozp0t8wsg/AABlwP-q-S1pOM4a9_RVAsXVa?dl=0
>> Note that even the piano keys are not flat pieces, they are wedges that 
>> thicken towards the back. Way more engineering and industrial design that 
>> you'd ever think for a research device. Beautiful piece of hardware, 
>> deserves to be 3D modelled. Good luck!
>> 
>> Marc
> 
> Marc,
>   Thanks!  I think I can work with those and get something out of it. given 
> the width of 5-3/4" (at its widest point?) and length of 6" I can scale the 
> rest.
> Like you said, Xerox put a lot of engineering design into the production 
> version, compared to the original Engelbart 'Demo' chordset (that someone has 
> now wired
> up to an iPad): 
> https://valerielandau.files.wordpress.com/2010/04/chorded-keyset-to-ipad.jpg
> 
> Steve
> 

Re: determing date on TI 99/4 computers.

[John Wilson via cctalk]

On Wed, Sep 06, 2017 at 02:07:22PM -0400, william degnan via cctech wrote:
>I'd double check that.   I have found, at least in my experience, that the
>beige are more plentiful than what you'd expect if they only made them for
>a few months.  I bet they were made for the last year or more of the run.

Is it possible to retrofit the beige keyboard?  I remember Radio Shack was
dumping surplus beige TI-99/4A keyboards super cheap for a while there, so
I was wondering if maybe people could've used them as repair parts?

Also, was there ever a TI-99, TI-99/2, TI-99/3 etc.?

The Bill Cosby TV ads were kind of embarrassing in retrospect ... but they
were funny at the time.  He didn't seem like much of a computer nerd.

John Wilson
D Bit

Re: determing date on TI 99/4 computers.

[Yeechang Lee via cctalk]

* Black and chrome, chiclet keyboard - TI-99/4, the first TI home
  computer (1979).

* Black and chrome, typewriter keyboard - TI-99/4A, the revised
  version of the above (1981).

* Beige, typewriter keyboard - TI-99/4A, cost-reduced version of the
  above (1983). Manufactured for only a few months before
  discontinuation in late 1983.

Re: determing date on TI 99/4 computers.

[william degnan via cctalk]

>
> * Beige, typewriter keyboard - TI-99/4A, cost-reduced version of the
>   above (1983). Manufactured for only a few months before
>   discontinuation in late 1983.
>

I'd double check that.   I have found, at least in my experience, that the
beige are more plentiful than what you'd expect if they only made them for
a few months.  I bet they were made for the last year or more of the run.
I know there were more than one ROM variation within the beige as well.  If
could be the last ROM variation was produced for the last few months, but
not all beige models.  Check the ROM chip silkscreen date codes perhaps to
confirm this.

Bill

Re: Computers before Information Theory

[Brent Hilpert via cctalk]

On 2017-Sep-06, at 11:03 AM, Paul Koning via cctalk wrote:
>> On Sep 6, 2017, at 1:25 PM, Fred Jan Kraan via cctalk 
>>  wrote:
>> 
>> While reading a biography of Claude Shannon, I try to get a picture how 
>> computers were seen and used before Information Theory emerged. It might be 
>> something like this:
>> 
>> Before Information Theory, computers were mainly calculators; processing 
>> programs from numbers put into the machine, much like programmable, but 
>> non-graphic calculators. Information Theory states that almost any digital 
>> encoded data can be processed, as long as you can teach the computer how to 
>> interpret the data.
>> 
>> Any more insights on this?
> 
> It seems to me that Turing's 1936 paper clearly takes the information theory 
> route.  Whether Babbage did I'm not sure.


While there was theory around before the machines, the stored-program machines 
made it concrete. 
Once numbers and programs were stored in the same memory and hence represented 
the same way it "brought home" or made concrete, aspects of the theory.
But that's not to suggest the theory was the driving force.
I have wondered just how much influence the latent theory that was around 
influenced the practical implementors of calculating machinery in that era of 
the mid-1940s,
the impression I have is not much, at least not in a recognisably causal or 
conscience manner.
My impression is the implementors at the time arrived at stored-program 
machines far more out of practical necessity than trying to enact, or even 
being much aware of, the theory.

Once those machines were implemented I think one of the first practical 
recognitions or uses of the data-vs-numbers, or symbols-vs-numbers, distinction 
would be assemblers.
When/what/who was the actual first assembler conceived or produced?

I think someone produced a graphical-display tic-tac-toe program for Whirlwind 
quite early, more a logic processing task than number-crunching.

However even before the stored-program machines, the Colossus machines (WWII) 
were more logic/symbol processors than numerical.
The SIGSALY digital voice encryption system (also WWII) was a mixture of 
digital numeric and logic processing for an objective that was not 
number-crunching.
Shannon was consulted during the design of SIGSALY, IIRC from reading.

But then also to keep in mind that Turing's work derives from Russell, et al 
reducing numbers and calculation to the more abstract notions of set theory, 
which - expressed in modern terms - was essentially declaring numbers and 
calculation to be a subset of 'information'.

That whole era of Nyquist/Shannon looking at the nature of information, Turing 
looking at highly abstract theory of symbol manipulation, and the implementors 
of calculating machines, that all came together to produce the modern computing 
and informatics world can be fascinating.

Scavenging higher-end models (Was: Re: determing date on TI 99/4 computers.)

[Tapley, Mark via cctalk]

On Sep 6, 2017, at 10:45 AM, Liam Proven via cctalk  
wrote:

> It shows what the machine could have been, if TI hadn't crippled it
> for fear of competing with its higher-end models.

I have heard similar arguments repeatedly, in reference to systems from 
multiple different companies (DEC in particular, but also IBM, TI as above, 
etc.).

It seems so short-sighted as to be almost improbable to me. Of *course* 
if a company can offer similar performance in a cheaper model, they should do 
that. The high-end customers will still pay premium for the slight extra 
performance, but the lower-end model will enable a whole cadre of users and 
developers which would otherwise have been priced away to the competition. 

Is this just 20/20 hindsight on my part, or are there factors I don’t 
understand in this decision? If it’s just internal company politics - high-end 
system group doesn’t want to get squeezed from below - the CEO’s job is to put 
a stop to that, I would think.
- Mark

Re: Computers before Information Theory

[Paul Koning via cctalk]

> On Sep 6, 2017, at 1:25 PM, Fred Jan Kraan via cctalk  
> wrote:
> 
> While reading a biography of Claude Shannon, I try to get a picture how 
> computers were seen and used before Information Theory emerged. It might be 
> something like this:
> 
> Before Information Theory, computers were mainly calculators; processing 
> programs from numbers put into the machine, much like programmable, but 
> non-graphic calculators. Information Theory states that almost any digital 
> encoded data can be processed, as long as you can teach the computer how to 
> interpret the data.
> 
> Any more insights on this?

It seems to me that Turing's 1936 paper clearly takes the information theory 
route.  Whether Babbage did I'm not sure.

paul

Computers before Information Theory

[Fred Jan Kraan via cctalk]

While reading a biography of Claude Shannon, I try to get a picture how 
computers were seen and used before Information Theory emerged. It might 
be something like this:


Before Information Theory, computers were mainly calculators; processing 
programs from numbers put into the machine, much like programmable, but 
non-graphic calculators. Information Theory states that almost any 
digital encoded data can be processed, as long as you can teach the 
computer how to interpret the data.


Any more insights on this?

Greetings,

Fred Jan

Re: HP 7970B Capstan?

[Chuck Guzis via cctalk]

On 09/06/2017 09:41 AM, Jon Elson via cctalk wrote:
> On 09/06/2017 11:03 AM, Al Kossow via cctalk wrote:
>>
>> On 9/5/17 11:09 PM, Chuck Guzis via cctalk wrote:
>>
>>> The read results have improved considerably.
>> tension arm servo acting reasonably?
>>
>> what style arm sensor does your drive have?

The same as shown in the 7970B/C service manual--a semicircular slotted
metal disk attached to the sensor arm intersecting a photocell/lamp box.

Looking at the drive casting, it's marked as a Rev F DHB, if that means
anything.  Just judging by the CE notes scribbled on the inside of the
door, I'm guessing that this is a late model.The write-enable sensor
assembly is different from that pictured in the service manual. The
sensor "finger" is attached to an L-shaped flat arm with two bolts for
adjustment.  I did replace the microswitch, as the lever arm had broken
off at some point.

> OK, so one of the first checks is to put a scope on the tach signal
> (should be a test point for that) and verify the velocity is a perfect
> trapezoid.  If there are regular spikes in the trace, that could
> indicate a problem in the tachometer.  If there are bobbles in the trace
> at jerk points, then adjusting the damping on the servo loop will help.
> 
> Then, you need a tape written at known density, and read that, looking
> at a data track.  The best is a tape with long records of all ones,
> which puts transitions on all channels (in 800 BPI NRZI mode).  Adjust
> the right pot to set the data rate to the calculated value for that
> drive's tape speed.
> 
> Then, move the scope to the skew test point.  The drive will have 9 FFs
> (one per track) and these go to a resistor summing point.  You should
> see nearly a square wave when skew is perfect, but will get much more
> slope with little steps on the flanks when skew is not good.  The
> all-ones tape is perfect for this adjustment.  You will see the shape of
> the signal fluctuate, as tape laying on the reel for some time will
> stretch just a bit, and tend to "weave" across the tape guides.  There
> will be adjusting screws to set the head skew to minimize this.
> 
> All the above applies mostly to 800 BPI NRZI.  PE and GCR are far less
> critical on this.

Will do--I've mentioned in another message that I'm preparing a test
tape using the drive, so I should get some inkling of timing and
adjustments pretty quickly.

--Chuck

Re: HP 7970B Capstan?

[Jon Elson via cctalk]

On 09/06/2017 11:03 AM, Al Kossow via cctalk wrote:


On 9/5/17 11:09 PM, Chuck Guzis via cctalk wrote:


The read results have improved considerably.

tension arm servo acting reasonably?

what style arm sensor does your drive have?




OK, so one of the first checks is to put a scope on the tach 
signal (should be a test point for that) and verify the 
velocity is a perfect trapezoid.  If there are regular 
spikes in the trace, that could indicate a problem in the 
tachometer.  If there are bobbles in the trace at jerk 
points, then adjusting the damping on the servo loop will help.


Then, you need a tape written at known density, and read 
that, looking at a data track.  The best is a tape with long 
records of all ones, which puts transitions on all channels 
(in 800 BPI NRZI mode).  Adjust the right pot to set the 
data rate to the calculated value for that drive's tape speed.


Then, move the scope to the skew test point.  The drive will 
have 9 FFs (one per track) and these go to a resistor 
summing point.  You should see nearly a square wave when 
skew is perfect, but will get much more slope with little 
steps on the flanks when skew is not good.  The all-ones 
tape is perfect for this adjustment.  You will see the shape 
of the signal fluctuate, as tape laying on the reel for some 
time will stretch just a bit, and tend to "weave" across the 
tape guides.  There will be adjusting screws to set the head 
skew to minimize this.


All the above applies mostly to 800 BPI NRZI.  PE and GCR 
are far less critical on this.


Jon

Re: HP 7970B Capstan?

[Al Kossow via cctalk]

On 9/5/17 11:09 PM, Chuck Guzis via cctalk wrote:

> The read results have improved considerably.

tension arm servo acting reasonably?

what style arm sensor does your drive have?

Re: determing date on TI 99/4 computers.

[Geoffrey Oltmans via cctalk]

On Wed, Sep 6, 2017 at 10:45 AM, Liam Proven via cctalk <
cctalk@classiccmp.org> wrote:

> On 6 September 2017 at 16:55, Geoffrey Oltmans via cctalk
>  wrote:
>
> > There's a pretty good article about TI's home computers that I've been
> > trying to find that lays out a pretty convincing argument for why the 4A
> > was not successful in the market despite early success.
>
> https://spectrum.ieee.org/tech-history/heroic-failures/
> the-texas-instruments-994-worlds-first-16bit-computer
>
> ...?
>

 That's a good article, but not the one I remember. The one I remember was
about three pages long and mentioned the AC adapter recall in particular.

Re: determing date on TI 99/4 computers.

[Liam Proven via cctalk]

On 6 September 2017 at 16:55, Geoffrey Oltmans via cctalk
 wrote:

> There's a pretty good article about TI's home computers that I've been
> trying to find that lays out a pretty convincing argument for why the 4A
> was not successful in the market despite early success.

https://spectrum.ieee.org/tech-history/heroic-failures/the-texas-instruments-994-worlds-first-16bit-computer

...?

Also see:

http://www.dvorak.org/blog/whatever-happened-to-the-texas-instruments-home-computer/

A more positive, nostalgic look:

https://www.theregister.co.uk/2017/02/27/community_builds_around_ti_99_4a/

There was a later successor model from another company, the Geneve
9640. A complete computer in its own right, it plugged into the
99/4A's Peripheral Expansion Box and totally replaced it.

It shows what the machine could have been, if TI hadn't crippled it
for fear of competing with its higher-end models.

http://www.old-computers.com/museum/computer.asp?c=1208=1

A bit more info including a scan of the product brochure:

http://www.mainbyte.com/ti99/geneve/geneve.html

-- 
Liam Proven • Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk • Google Mail/Talk/Plus: lpro...@gmail.com
Twitter/Facebook/Flickr: lproven • Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 • ČR/WhatsApp/Telegram/Signal: +420 702 829 053

Re: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED utilities

[Mark Darvill via cctalk]

I am in the UK and I have bid for these today and will image them if I win them.

Mark

On 6 Sep 2017, at 15:11, N0body H0me via cctalk  wrote:

>> -Original Message-
>> From: cctalk@classiccmp.org
>> Sent: Wed, 6 Sep 2017 08:37:58 +0200
>> To: cctalk@classiccmp.org
>> Subject: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED
>> utilities
>> 
>> Someone in the UK is selling a lot of floppy disks (shipping to UK only).
>> Labels mentions "Andromeda Systems WDLT DL/DY Utilities", "WDC11 support
>> disk" and "Advanced Electronic Design WINC-05/8"
>> 
>> Unless this type of software isn't already imaged and saved it might be
>> useful if someone in the UK would buy them and image them.
>> 
>> http://www.ebay.com/itm/222629853408
> 
> For once, an e-bay auction description of RARE is actually warranted
> and accurate.  In my experience, Andromeda Systems material of *ANY*
> stripe is pretty rare-- and there's almost nothing on Bitsavers.
> 
> These controllers show up in systems from time to time, but this is
> the first time I've seen the software for them
> 
> 
> N0body
> 
> 

Re: Odd Ebay auction showed up today...

[dwight via cctalk]

The seller is in business. Old computers seem to be the target. They do not 
seem to have much computer knowledge. They seem to be a member of VCF and such 
as a business would be that sells such items. anyone can be a member They 
periodically change their seller name. They don't seem to be interested in 
having people correct their descriptions of items(personal experience).

I what their ebay sales with curiosity now. They do sell some items every now 
and then. I suspect it is enough to justify their efforts.

I've not found anything that they sell to be at a reasonable pricing but that 
is just my personal opinion.

Dwight




From: cctalk  on behalf of Sam O'nella via 
cctalk 
Sent: Tuesday, September 5, 2017 7:24:41 PM
To: Warner Losh; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Odd Ebay auction showed up today...

Since it wasn't said already, i think (if its the same user) they've posted 
similar auctions several times in the past also (over several years). You can 
see some of us discuss it in vcfed.org forums.
No affiliation or bad blood myself. I know i bought my working Columbia Data 
Products luggable from them years back. But i know they have premium/eBay 
prices generally.
We also occasionally see the reminder that the user is a member of the 
community and on some forums so despite opinion its a bit ashame to see bad 
mouthing of any collector. Albeit actual sales, and comments from first hand 
deals are certainly legitimate information.
null

Re: determing date on TI 99/4 computers.

[Geoffrey Oltmans via cctalk]

Depends on if you're talking about the 99/4 or 99/4A. The 99/4 was black
and silver and had a chiclet style keyboard and is rare. The 4A had a black
and silver finish first, and then later switched to beige I imagine in an
effort to curb costs since they were being undercut pretty badly by
Commodore.

There's a pretty good article about TI's home computers that I've been
trying to find that lays out a pretty convincing argument for why the 4A
was not successful in the market despite early success. Basically a costly
recall of the power supplies wiped out a lot of their profits, and the
system was too expensive due to the insistence of using as much in-house
parts as possible even when there were much cheaper components available in
the wider market, for example the CPU (Z80 or 6502).


On Wed, Sep 6, 2017 at 1:00 AM, Ed via cctalk  wrote:

> There is a white  or beige one
>
> then there is the black and chrome  one?
>
> which  first?  and  dates please?
>
> This is unfamiliar territory  for me.
> but need to pay homage to these
> in a museum display here.
>
> looking  for  good  hi res scans of
> adv. material etc. for  display??
>
> thanks  ed# _www.smecc.org_ (http://www.smecc.org)
>

NEC D2246 SMD Disk Drives on ebay , brand new sealed old stock

[Mazzini Alessandro via cctalk]

Maybe someone is interested.

http://www.ebay.com/itm/NEC-D2246-8-0-FHT-SMD-DISK-DRIVE-UN-TESTED-NEW-OLD-S
TOCK-RARE-VINTAGE-/253049784698

apparently new old stock, sealed, and in quantity

(I'm not related)

RE: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED utilities

[N0body H0me via cctalk]

> -Original Message-
> From: cctalk@classiccmp.org
> Sent: Wed, 6 Sep 2017 08:37:58 +0200
> To: cctalk@classiccmp.org
> Subject: EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED
> utilities
> 
> Someone in the UK is selling a lot of floppy disks (shipping to UK only).
> Labels mentions "Andromeda Systems WDLT DL/DY Utilities", "WDC11 support
> disk" and "Advanced Electronic Design WINC-05/8"
> 
> Unless this type of software isn't already imaged and saved it might be
> useful if someone in the UK would buy them and image them.
> 
> http://www.ebay.com/itm/222629853408

For once, an e-bay auction description of RARE is actually warranted
and accurate.  In my experience, Andromeda Systems material of *ANY*
stripe is pretty rare-- and there's almost nothing on Bitsavers.

These controllers show up in systems from time to time, but this is
the first time I've seen the software for them


N0body

RE: HP 7970B Capstan?

[Rik Bos via cctalk]

> -Oorspronkelijk bericht-
> Van: cctalk [mailto:cctalk-boun...@classiccmp.org] Namens Chuck Guzis via
> cctalk
> Verzonden: woensdag 6 september 2017 8:09
> Aan: CCtalk 
> Onderwerp: Re: HP 7970B Capstan?
> 
> On 09/05/2017 10:47 PM, David Collins wrote:
> > From my old HP CE days you could always get black off the capstan if
> > you used alcohol or similar (never recommended). The key thing is it
> > shouldn't be sticky/gooey.
> 
> I noticed the issue by starting a read from load point and observing that the 
> bit
> timing and data was all over the place until things came up to speed. I was
> getting different data with each try.
> 
> I pulled the capstan off, cleaned the powdery stuff off with isopropanol
> and gave it a 30 minute soak in methyl salicylate and isopropanol.   The
> capstan comes out clean (no more shedding) and firm.
> 
> I also noticed that the bits of foam on the inside of the capstan had 
> degraded to
> goo.  I replaced those with some new foam.
> 
> The read results have improved considerably.   Not perfect, but much better.
> 
> --Chuck

Chuck,

The tacho is a combined motor generator unit, it could be a good idea to read 
the adjustment procedures for the capstan tacho.
The behavior is electronic controlled and adjustable.
You can find the manual at the HP Museum site: 
http://www.hpmuseum.net/document.php?hwfile=2807
7970CEAdjusment...etc shouldn't be difficult to find.
The speed and transient behavior of the capstan should be checked and possibly 
adjusted.
You should also check if the capstan turns easy without noise.

-Rik

Re: Xerox Alto Chordset Pictures (was RE: VCF?)

[Steve Malikoff via cctalk]

> Steve,
>
> Here you go, 13 pictures of the Chordset. That's about as orthoscopic as I 
> could get them.
> https://www.dropbox.com/sh/owjnyvozp0t8wsg/AABlwP-q-S1pOM4a9_RVAsXVa?dl=0
> Note that even the piano keys are not flat pieces, they are wedges that 
> thicken towards the back. Way more engineering and industrial design that 
> you'd ever think for a research device. Beautiful piece of hardware, deserves 
> to be 3D modelled. Good luck!
>
> Marc
>
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Steve 
> Malikoff via cctalk
> Sent: Sunday, September 03, 2017 9:16 PM
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: VCF?
>
>
> Marc said
>> Problem is, it's not like this simple drawing at all, it's much more 
>> complicated. Every surface is slanted, edges are rounded, edges are 
>> beveled... Quite a refined industrial design actually.
>> Marc
>>
>> On Aug 13, 2017, at 11:26 PM, ste...@malikoff.com wrote:
>>
>> Marc said earlier:
>>> The overall Chordset dimensions are 5 3/4 for width and 6" for depth. Keys 
>>> are spaced like regular piano keys, whatever that is. That should help you 
>>> dimension the drawing you have. We found very few programs that would use 
>>> it.
>>> Marc
>
> Marc
> I'd be happy with a few top, side, front, back, bottom photos taken flat-on, 
> and a 3/4-front and 3/4-rear photo. If there is a round flat object of a 
> known size (eg. a coin) placed against each surface before taking the 
> picture, then I can apply some basic photogrammetry techniques and/or affine
transformations to get enough information. I usually do this to extract and 
generate plan/elevation/front views and marking details of WW2 vehicles from 
photos, have also done for a> 360/40 CPU and operators table display (drawings 
are done but need dimensioning - need someone to confirm measurements someday).
> So, basically some photos would be fine, if that's ok. No hurry - it's just 
> an idle thought project I've had for a while, I have (too) many other things 
> to work on :)
>
> Steve.



Marc,
   Thanks!  I think I can work with those and get something out of it. given 
the width of 5-3/4" (at its widest point?) and length of 6" I can scale the 
rest.
Like you said, Xerox put a lot of engineering design into the production 
version, compared to the original Engelbart 'Demo' chordset (that someone has 
now wired
up to an iPad): 
https://valerielandau.files.wordpress.com/2010/04/chorded-keyset-to-ipad.jpg

Steve

Re: determing date on TI 99/4 computers.

[Ed via cctalk]

In a message dated 9/5/2017 11:27:04 P.M. US Mountain Standard Time,  
p...@mactec.com.au writes:

Hi  Ed
Howdy!



Did you do any research on this at all?
 
Not a lot   found a few conflicting things
 



The beige one was later.
Thanks -



https://en.wikipedia.org/wiki/Texas_Instruments_TI-99/4A


Bill  Cosby was their spokesperson. I can scan the advertising stuff that I 
have,  but I’m pretty sure that it is all online somewhere.

Good  hi  res scans  appreciated
 
Ed#..  Thanks !



> On 6 Sep 2017, at 4:00 pm, Ed via cctalk   wrote:
> 
> There is a white   or beige one
> 
> then there is the black and chrome   one?
> 
> which  first?  and  dates please?
>  
> This is unfamiliar territory  for me.
> but need to pay  homage to these
> in a museum display here.
> 
>  looking  for  good  hi res scans of
> adv. material etc.  for  display??
> 
> thanks  ed# _www.smecc.org_  (http://www.smecc.org) 

EBAY - DEC RX01/02 floppy disks - Andromeda Systems and AED utilities

[Mattis Lind via cctalk]

Someone in the UK is selling a lot of floppy disks (shipping to UK only).
Labels mentions "Andromeda Systems WDLT DL/DY Utilities", "WDC11 support
disk" and "Advanced Electronic Design WINC-05/8"

Unless this type of software isn't already imaged and saved it might be
useful if someone in the UK would buy them and image them.

http://www.ebay.com/itm/222629853408

Re: determing date on TI 99/4 computers.

[Chris Pye via cctalk]

Hi Ed

Did you do any research on this at all?

The beige one was later.

https://en.wikipedia.org/wiki/Texas_Instruments_TI-99/4A


Bill Cosby was their spokesperson. I can scan the advertising stuff that I 
have, but I’m pretty sure that it is all online somewhere.



> On 6 Sep 2017, at 4:00 pm, Ed via cctalk  wrote:
> 
> There is a white  or beige one
> 
> then there is the black and chrome  one?
> 
> which  first?  and  dates please?
> 
> This is unfamiliar territory  for me.
> but need to pay homage to these
> in a museum display here.
> 
> looking  for  good  hi res scans of
> adv. material etc. for  display??
> 
> thanks  ed# _www.smecc.org_ (http://www.smecc.org) 

Re: HP 7970B Capstan?

[Chuck Guzis via cctalk]

On 09/05/2017 10:47 PM, David Collins wrote:
> From my old HP CE days you could always get black off the capstan if
> you used alcohol or similar (never recommended). The key thing is it
> shouldn't be sticky/gooey.

I noticed the issue by starting a read from load point and observing
that the bit timing and data was all over the place until things came up
to speed. I was getting different data with each try.

I pulled the capstan off, cleaned the powdery stuff off with isopropanol
and gave it a 30 minute soak in methyl salicylate and isopropanol.   The
capstan comes out clean (no more shedding) and firm.

I also noticed that the bits of foam on the inside of the capstan had
degraded to goo.  I replaced those with some new foam.

The read results have improved considerably.   Not perfect, but much better.

--Chuck

determing date on TI 99/4 computers.

[Ed via cctalk]

There is a white  or beige one
 
then there is the black and chrome  one?
 
which  first?  and  dates please?
 
This is unfamiliar territory  for me.
but need to pay homage to these
in a museum display here.
 
looking  for  good  hi res scans of
adv. material etc. for  display??
 
thanks  ed# _www.smecc.org_ (http://www.smecc.org)