June 2021 - vcf-midatlantic

Re: [vcf-midatlantic] Tales from the Repair Workshop 6/12 & 6/13, 2021
by Daniel Fitzgerald 17 Jun '21

17 Jun '21

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High Scores on Netflix
by Jeffrey Brace 16 Jun '21

16 Jun '21

Just started watching a new show on Netflix called "High Scores". It highlights different videogame history (of the 80's) phenomena each episode. It reminds me of the 2000's show "Icons" which did something similar: https://en.wikipedia.org/wiki/Icons_(TV_series) So far I like it a lot! Great fun and learning some history that I didn't know. ========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey(a)vcfed.org

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Museum Report 2021-06-12 & 2021-06-14
by Jeffrey Brace 16 Jun '21

16 Jun '21

Saturday and Sunday a super high interest guy came. I think he was about late high school age and visiting from Georgia. He stayed Saturday for hours and was programming BASIC on the Zorba by himself. He asked to borrow a Microsoft BASIC manual so I gave him one from the IBM 5150 and off he went. I don't know what his end product was as I was busy with the repair workshop that day and couldn't stick around. Dennis can fill us in as he was docent that day. On Sunday he came back again and was programming on the TRS-80. He used the TRS-80 Graphics Programming book as a reference and created an etch-a-sketch program. It's quite rare for a visitor to stay for hours like that and sit down and program on these machines. From time to time I will get visitors that are patient enough to sit down, type in a short program and teach them the basics of BASIC programming. ========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey(a)vcfed.org

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Tales from the Repair Workshop 6/12 & 6/13, 2021
by Jeffrey Brace 16 Jun '21

16 Jun '21

I have two tales to tell about the repair workshop that are funny, but I won't tell them here. You will have to ask me in person, but I intend to repeat them over and over again until people get sick of me telling them. Then I will tell new stories. The repair workshop was well attended this time with the usual suspects and some new ones as well. Jeff Salzman and Herb got the H89 working! So now it is available for operation and display in the museum. I thank them very much for all their hard work in working on the repair of the machine and getting it into operation. It has been sitting in the museum for years as a static display and it is lovely to see it actually display something on the screen and operate. We have Vcalc and 1 or 2 other pieces of software (I forget what they are at the moment). Jeff Salzman intends to make other software disks available to the museum the next time he comes or he can give me the disks at the July repair workshop @ System Source. David Gesswein worked on the PDP 8. The original intention was to train me on papertape and software loading, but he discovered that there were some faults. He had suspected it to be one problem on two cards, but that wasn't the case. He found out one of the diodes needed replacement and it worked better. However there was another problem on another card, but he ran out of time and will take the card home to troubleshoot and narrow down the problem. I know that others were working on various things, but I didn't have time to get details. Always a fun time at the workshop and lots of stuff getting fixed. Going to Brick House Tap & Tavern was a welcome change. Main Street Bar and Grill is nice, but we have overdone it and needed to change up things. I'm considering doing an outdoor grill at the August repair workshop cooking burgers and hotdogs. Next repair workshops are: July 10 & 11 @ System Source : SIGNUP <https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hE…> August 14 & 15 @ InfoAge: SIGNUP <https://docs.google.com/spreadsheets/d/1J028DlSdvSUlh3BsrGfmalHQ9qbFfPSUQa9…> ========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey(a)vcfed.org

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MICRO (6502) magazine article index by system
by Bill Degnan 15 Jun '21

15 Jun '21

If anyone is interested and it's not already published WWW-wise, I scanned the "MICRO index by system" published by MICRO magazine, which ran from 1977 to 1980 or 1981. I found the index within a stack of MICRO magazines I have been moving around. This is useful to have because MICRO had a lot of useful technical info relating to the 6502-based micros of the time period. It's hard to search the web for "micro index" - one just gets a lot of nasdaq stock stuff. I did not check 6502 or other archive sites, this may already be listed there, but here it is again https://www.vintagecomputer.net/browse_thread.cfm?id=783 Bill

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July Repair Workshop @ System Source
by Jeffrey Brace 15 Jun '21

15 Jun '21

The July Repair Workshop will be at System Source. Signup here: https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hE… The Vintage Computer Federation and the System Source Computer Museum are hosting a vintage computer workshop on Saturday July 10th and Sunday July 11 th 2021 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) ON SATURDAY we will open at 9:00 AM and will lock up by 7:30 PM. We will go to dinner afterwards. If you are interested in dinner, then please indicate on the signup form here: https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hE… ON SUNDAY: We will open at 9:00 AM and lock up at 5:00 PM Accommodations: Try https://www.tripadvisor.com/Hotels-g41196-Hunt_Valley_Maryland-Hotels.html <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.tripadvisor.com_Ho…> Feel free to talk with others about sharing a room. Food: There are plenty of restaurants within a short drive. We will have a 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 - Preview/contribute to new exhibit IBM PC@40 We will have most of the IBM PCs (and predecessors) load up with various operating systems and software If you need a machine to work on, please let me know. We have lots of computers awaiting restoration! Let others know what you are working on. 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

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Tales from the Repair Workshop 6/12 & 6/13, 2021
by Herb Johnson 14 Jun '21

14 Jun '21

Heath H89 (actually an H88 upgraded) At the May workshop on the museum H89, I replaced some 20V caps on a 20V DC line on the CPU board. This is a common H89 problem where the caps short out on a DC line that's over-voltage. Jeff Saltsman also at the May workshop, repaired his own H89 floppy drive which had gummy disk-hub bearings. I did the same repair on the museum H89 drive; we both succeeded. So the museum H89 would boot HDOS but the keyboard returned odd codes on several keys. Jeff later "repaired" the floppy controller board. There was also an H89 in pieces in a box (not Heath box) which looked ripe for parts. At the June workshop, I found on the H89 a damaged keyboard encoder chip on the terminal board. I replaced keyboard and chip from the box o' H89 items. A terminal board from the box failed with smoke and flame. Again a capacitor short which I fixed but to no good result; but it sourced the keyboard encoder chip. That fixed the funny-keys problem. A surprising amount of rust was found at the bottom of the museum H89 which I partly cleaned. Also I repaired by replacement, the recently-repaired floppy controller board, with a swap from the boxed H89. Thus it's useful to have multiple and even damaged duplicate computers in the Warehouse. Jeff Saltzman provided assistance and test disks, as he did in May. He'll provide some disks for the Museum's use. I suggested he pull the floppy drive from the boxed H89 and restore that drive. It likely needs the same repair as previous drives; these are all the same model. The H89 now boots and operates CP/M and HDOS from its internal floppy drive. It's useful for demonstration but may need more testing. I"ve brought home the museum's external H89 drive in cabinet, for restoration. Of course I'll return it when I can, say within a month. I'll have a Web page to show the various repairs, among my other H89 repair pages at retrotechnology.com DSD floppy drive/controller Work for myself was on a PDP-8 compatible floppy drive system by DSD. I had duplicate hardware and assistance from David Gesswein. His extra drive cabinet completed my drive controller and Shugart drives. I built flat-cables and assembled and cross-tested both DSD units. David and I got mine working! (The controller has a local-test mode, no PDP-8 needed.) I may have a floppy-drive system for my PDP-8/F! I'm grateful for David's help and equipment and his time. Others I only wish I could have helped David with the Straight 8's problem; it's tech on the trailing edge of my experiences. 1960's transistor logic is not 1970's TTL logic! One card is equivalent to a few TTL chips if that. We are so lucky that TTL has endured half a century or so. David provides an account. You won't find that detail anywhere else! And I was able to help Dan FitzGerald with some Apple Mac equipment, as Dan had requested on the Google registration form. I provided some moral support for others at the workshop. But I likely missed other workshop activities as they were in two other rooms. Busy weekend. regards, Herb -- 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 comcast DOT net

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Re: [vcf-midatlantic] Tales from the Repair Workshop 6/12 & 6/13, 2021
by Ethan O'Toole 14 Jun '21

14 Jun '21

[NON-Text Body part not included] System source is in MD outside of the Baltimore and DC areas. It's awesome. - Ethan

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Bernie S paid a visit!
by Herb Johnson 13 Jun '21

13 Jun '21

> Bernie S paid a visit on May 16 at the very end of our repair workshop. He > had brought some items for Dmitry. One thing was a custom built 6502 system > with all sorts of wires. Another one was a custom built Apple // clone. > Very interesting to see all these items. The photos reveal, some kind of late 1970's, hand-wired cassette-based computer of some sort. And some kind of massively reworked possibly-Apple-II motherboard surrounded by hand-wired boards. Jeff, were you told some kind of history associated with these constructions? Otherwise for anyone not alive in the era, these will be indecipherable pieces of chips and boards. And, that applies to most people interested today. I'll give some interpretation, otherwise this stuff looks awful from a 21st century view; and that saddens me. Without my seeing them myself - I was on campus but unaware - all I can say from the era, is that many techs were obliged to wire up their own computers from pieces of other digital technology. Why? Because computers were not available or too expensive on the one hand, and pieces and parts of older computing tech were available cheaply on the other hand. And some people had the ability, tools and parts to design (or copy) and hand-wire their own boards. Those skills were valuable in the years before (and after) personal computers started becoming available. When personal computers became CHEAP and available, this technology was abandoned - that's why it's all dusty and rusty. And so that's what you see now. Regards, Herb -- 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 comcast DOT net

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Wanted: Tandon TM100-2A
by Mike Loewen 12 Jun '21

12 Jun '21

Does anyone have a working Tandon TM100-2A for sale? IBM faceplate okay, too. Mike Loewen mloewen(a)cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/

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