[vcf-midatlantic] Museum Artifact Report

Jeffrey Brace jeffrey at vcfed.org
Fri Oct 13 18:49:35 EDT 2017


We appreciate whatever work you do to repair the TR-20! It's a hobby after
all! It will be great to see it actually work instead of just looking at a
static artifact!

Jeff Brace

On Fri, Oct 13, 2017 at 12:53 PM, Bill Inderrieden via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> ---------- Forwarded message ----------
> From: SVCatITC at aol.com
> To: vcf-midatlantic at lists.vintagecomputerfederation.org
> Cc:
> Bcc:
> Date: Fri, 13 Oct 2017 12:53:19 -0400
> Subject: Museum Artifact Report
> Hello All;
> I figured it was time, (Since the UNIVAC Pix spread was sent by Bill  D.)
>  that I would also update us all on the progress of getting the  EAI TR20
> back
> on line.
> 1. Progress is slow, but moving forward on getting a decent stable
> reference
>     in the test bed for doing integrator tray testing  from our TR20.
>     The test bed has to undergo some major revamp to make  room for more
>     test components to use with the main test  evaluations.  We are doing
> that
>     revamp and fabrication here at my shops.
>     Reference components have been purchased and now have to  be installed.
> 2. A master 10 volt reference, to be used for setup and maintenance of  the
>     rack reference, as well as the test bed reference, has  been purchased.
>     This reference is good to better than 0.02 %   error, which will be 5x
> better
>     than we need for computation.
> 3. I still need to get out to a machine shop to fabricate the wheeled
> dolly for
>    the main rack display.  This will allow us to roll the  rack in and out
> of it's
>    berth for easy maintenance access.
> 4. Back lighting has been purchased for accent lighting on the TR20 while
> in
>     the rack, as it will be in shadows when the  XY plotter gets installed.
> 5. The TR20 main power supply oscillates at high frequency.  Being  an
>     alumnus of EAI, I fought this problem in these supplies  when working
> there.
>     The solution has already been installed in the test bed,
>     (as my supply did also osc. in the bed).   I have more updated parts to
> install in a
>     duplicate 10.179 supply, which will then be installed in  the TR20.
>     The original supply will be left untouched and be  put "under
> Plexiglas"
>     to show the workmanship to visitors.   This  update will also be done
> to
>     the 10 volt reference in the rack and the original rack  tray be put
> under
>     glass as well for viewing.
> The work goes slow as I have had several "real job" work projects and
> "life stuff"
> that has gotten in the way of doing this fun stuff.
> I will try and give further updates as they move forward.
> Bill Inderrieden.

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