December 2019 - vcf-midatlantic

Museum Report 2019-12-15 December, 15, 2019
by Jeffrey Brace 15 Dec '19

15 Dec '19

Today was very busy with lots of visitors due to the model train holiday show. So I was busy from 2:30 to 4:30 almost continuously. One visitor was one of the RESISTORS and came with his son, so I showed him the PDP 8 and told him the history of it. The father corrected some of the story. Also met a guy who was best friends with Ken Thompson's son. So a very interesting day with a range of visitors and interest levels. Tony and Adam were here also removing the Featured Artifact (Cannon Cat) and replacing it with a BeBox. Tony and Adam also worked on other museum warehouse stuff. -- ========================================= Jeff Brace Vice President Vintage Computer Federation

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OT: Do we have a VARIAC in the VCF/CDL lab?
by Martin Flynn 14 Dec '19

14 Dec '19

Camp Evans had a bit of an electrical supply issue a few weeks ago, so the usual suspects from CDL are deploying a power quality / power loss alarming system. ANSI C84.1-2011 states that 197.6 to 218.4 VAC is the acceptable voltage range on our service type (120/208 3ø AC) I need a way to simulate an out of range voltage in order to confirm the trigger relays operate as intended Martin Flynn

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Post Festivus notes and questions
by Herb Johnson 13 Dec '19

13 Dec '19

> When mentioning the nice new Processor poster on Saturday I'd like to > note that a visitor said it was pretty but was so small it was > impossible to read. Lots of discussion about a magnifier, reading glasses, etc. for a large poster with tiny print, which resides outside the VCFed InfoAge museum. I retain the subject-line for continuity. I think the primary point of the poster in-place, is to suggest the extensive history. Not to document every bit for every visitor who is interested. While magnifiers and better lighting have merits, I have additional suggestions. 1) Post nearby, a Web link, maybe also a QRL-code or whatever-the-hell they call those blocky-things that 'phones can scan, to the Web site of the producer of the poster. If the Museum is producing a take-away document for visitors, include a reference there. 2) If said poster is of interest, perhaps the Museum can offer some for sale? For the usual reasons museums do that. 3) Make available to docents (or whatever VCFed calls museum volunteers on duty), a form of the poster in larger type, in booklet form. Those interested can request a look at the booklet for detailed reading. This may also encourage sales of the poster. I presume, the effort to enlarge, paginate and print one copy is not onerous. The Museum has a color printer; I presume a PDF of the poster is available. All this said: this poster is not the product of the VCFed, it's an item bought for display and for purpose. But let's "feed the hungry bee". If visitors show interest in the item, the VCFed might consider making copies available, provide a more readable version on-site, and glean income from doing so. As for a magnifier, they and a string are available for some few dollars. But they could become a nuisance for any kid that wants to use it as a tether-ball. I think my suggestions are accommodations which serve the purpose; plus offer revenue and/or take-homes for visitors. My several cents, Herb Johnson -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing

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Repair Workshops 2020
by Jeffrey Brace 13 Dec '19

13 Dec '19

Two repair workshops in January: One is at Bill Degan's "Kennett Classic" in Kennett, PA on January 4 The other is at InfoAge on January 25 & 26 in the CDL Hackerspace. There is a limit of 20 tables at one time, so be sure to sign up to guarantee a table. Signup Sheets: January 4, 2020 : Kennett, PA. at Bill Degnan's Kennett Classic Let him know that you are coming: <https://www.vintagecomputer.net/contact.cfm> or Meetup Group: <https://www.meetup.com/Kennett-Classic/events/266463968/> Facebook: <https://www.facebook.com/kennettclassiccomp> Website: < https://www.kennettclassic.com/> January 25 & 26, 2020: InfoAge CDL Hackerspace building 9059 < https://docs.google.com/spreadsheets/d/1LmYNLLK6CEOLCeOQCClhe1J20gpmVlyzmSs… > February 15 & 16, 2020: Hunt Valley, MD at Bob Roswell's System Source: < https://docs.google.com/spreadsheets/d/1cVBh27hzT1P53BCorZXcK3cZQVwPtwWLLX6… > March 7 & 8, 2020: InfoAge CDL Hackerspace building 9059: < https://docs.google.com/spreadsheets/d/1DySkGulduRUxJuPwK2RUEdP_yKD8YiDEn7K… > April 4 & 5, 2020: InfoAge CDL Hackerspace building 9059 < https://drive.google.com/open?id=1VTM4R1HBKCcal7FAG_SslXv4jPAyuvygIkVErAKTp… > -- ========================================= Jeff Brace Vice President Vintage Computer Federation

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Kind of off subject: Need Help running cable for VCF
by Martin Flynn 12 Dec '19

12 Dec '19

Hi Folks, * CDL has the network cable to support building 9010 in place. We could use a hand running the network cables from the VCF area into the next "H" section (9010B) Would be a total of three cable, two for cameras in the hallway, and one to the firewall in the VCF rack * Other projects include cutting unistrut and mounting the rack on the brick wall in 9010B. We scheduled for December 21st, starting around 11:00 AM Off list replies prefer to prese the S/N radio of the list. Martin Flynn

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Reforming capacitors
by Herb Johnson 12 Dec '19

12 Dec '19

Bill S. says: "The only issue was that all of the [Processor Tech SOL] unregulated S-100 supplies were out of spec. This turns out to be a design issue, with a specific engineering note to address it (adding a bucking transformer) which I applied." - end quote Bill, for those not in-the-know: a "bucking transformer" reduces AC voltage by turning a transformer into an autoformer; by connecting the secondary in reverse and in series with the primary, to reduce the output voltage. One can also use a reducing transformer of course. That's too brief but some Web searching will explain further. Point being: many vintage computers of the 70's which use dem big transformers, expect line voltage to be 110 volts. Modern AC line voltage may be 120 volts; mine is about 122. I've had Heath/Zenith H89's blow up their regulator tantalums because the unregulated DC to their little DC regulators, exceeded the voltage ratings! Again, review H89 schematics for details. And of course, S-100 computers with non-switching power supplies and only a few S-100 cards to power, often produce excessively high unregulated DC voltages to the S-100 card DC regulators. As in IMSAI. I too have had to either a reducing transformer, rig a 12V AC transformer to "buck", and/or upgrade tantalum caps to higher voltage ratings (or replace same when they shorted). Or, just run the thing off a Variac. This was a good discussion. I will capture it for future reference, and possibly ask the participants privately if I can include their notes on my Web site; where I have similar information. Regards, Herb "pop!" Johnson -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing email: hjohnson AT retrotechnology DOT com or try later herbjohnson AT retrotechnology DOT info

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Kennett Classic Workshop 1/4/2020
by Bill Degnan 11 Dec '19

11 Dec '19

If you're interested in attending the vintage computing workshop at KC 1/4/2020 please let me know via https://www.vintagecomputer.net/contact.cfm or the meetup group I created, signup here: https://www.meetup.com/Kennett-Classic/events/266463968/ https://www.facebook.com/kennettclassiccomp https://www.kennettclassic.com/ Moving forward Jeff Brace and I are going to talk about coordinating our workshops and possibly hosting a VCFed workshop at Kennett Classic. For directions and hours https://www.kennettclassic.com/ Bill

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VCF Mid-Atlantic Calendar Updated
by Jeffrey Brace 11 Dec '19

11 Dec '19

I updated the events on the Calendar: http://vcfed.org/wp/groups/vcf-mid-atlantic/vcf-mid-atlantic-calendar/ -- ========================================= Jeff Brace Vice President Vintage Computer Federation

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February Repair Workshop at System Source in Maryland
by Jeffrey Brace 11 Dec '19

11 Dec '19

The Vintage Computer Federation and the System Source Computer Museum are hosting a vintage computer workshop on Saturday February 15th and Sunday February 16th 2020 at: System Source Computer Museum 338 Clubhouse Road, Hunt Valley, MD 21031 Plenty of free parking, short walk from Baltimore’s light rail (Gilroy Road Stop) We will open at 10AM on Saturday February 15th, 2020 and will lock up by midnight. We will open at 10AM on Sunday February 16h and lock up at 6:00PM Accommodations: Try https://www.tripadvisor.com/Hotels-g41196-Hunt_Valley_Maryland-Hotels.html Feel free to talk with others about sharing a room. Food: There are plenty of restaurants within a short drive. We will have catered Indian buffet on Saturday at cost ($12.00?) and catered Barbecue ($12.00?) on Sunday for those who sign up. We will feature tours of the museum throughout both days and several mini-workshops: - Retrobright workshop (bring your yellowed plastics) - Pre-industrial computing class - Learn to use a slide rule, and various types of Abaci - Hot Metal Typesetting (3500 lb word processor) If you need a machine to work on, please let me know. We have lots of computers awaiting restoration! If you have unusual needs, (220 Volts, fork lift, etc please email Bob Roswell at museum(a)syssrc.com Bob Roswell broswell(a)syssrc.com https://museum.syssrc.com 410-771-5544 x 4336 Here is the signup sheet: < https://docs.google.com/spreadsheets/d/1cVBh27hzT1P53BCorZXcK3cZQVwPtwWLLX6… > ========================================= Jeff Brace Vice President Vintage Computer Federation

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MD event in February?
by Blake Patterson 11 Dec '19

11 Dec '19

I hear there is a gathering in February in Maryland. The calendar page is throwing a 503 right now, so can't see details. Is there info out there on this? I am fairly local to this. Thanks. bp :: bytecellar.com

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