Bill, 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@lists.vintagecomputerfederation.org> wrote:
---------- Forwarded message ---------- From: SVCatITC@aol.com To: vcf-midatlantic@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.