January 2023 - vcf-midatlantic

Re: [vcf-midatlantic] Repair Workshop reminder 1/14 & 1/15, 2023
by Neil Cherry 13 Jan '23

13 Jan '23

On 1/13/23 10:34, Jonathan Sturges via vcf-midatlantic wrote: >> Reset sees a low (/RST) every 3s. So there is a watchdog timer setup. I traced it back to a MC14584B (yea!) which is a hex >> schmidt trigger (what? 😉 ). So I have to do some more tracing but the MC14584B is socketed so I'll build a manual reset >> circuit and figure out what is going on later. > Ahh, the Schmidt trigger. Pairs of those gates are good for fixing marginal amplitude issues and/or "squarifying" a > less-than-square waveform. If the RST signal looks well-formed, then the problem is probably upstream of the Schmidt trigger. I pop'd the chip out and soldered up a resistor, cap and NO PB on a carrier. I'll search for the watchdog later. That solves that problem for now. The new troublemaker is the USB dongle doesn't have enough oomph to pull up the 6803 Rx pin. I'm going to drive it with either a NOT or NAND gates or an opto to drive it a bit more. -- Linux Home Automation Neil Cherry kd2zrq(a)linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies KD2ZRQ

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Re: [vcf-midatlantic] Repair Workshop reminder 1/14 & 1/15, 2023
by Jonathan Sturges 13 Jan '23

13 Jan '23

-----Original Message----- From: Neil Cherry via vcf-midatlantic <vcf-midatlantic(a)lists.vcfed.org> Subject: Re: [vcf-midatlantic] Repair Workshop reminder 1/14 & 1/15, 2023 > Reset sees a low (/RST) every 3s. So there is a watchdog > timer setup. I traced it back to a MC14584B (yea!) which is a hex > schmidt trigger (what? ;-) ). So I have to do some more tracing but the > MC14584B is socketed so I'll build a manual reset circuit and figure out what is > going on later. Ahh, the Schmidt trigger. Pairs of those gates are good for fixing marginal amplitude issues and/or "squarifying" a less-than-square waveform. If the RST signal looks well-formed, then the problem is probably upstream of the Schmidt trigger. -Jonathan

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Jan 2023 Repair Workshop Info
by Jeffrey Brace 13 Jan '23

13 Jan '23

Signup for January 2023 Repair Workshop here: January 2023 Repair Workshop Signup Sheet <https://docs.google.com/spreadsheets/d/1-CzOmtnbGWwcNc53ewymcAe1Zt5xNTow4cm…> Spaces are first come first serve to the CDL space. Limited space available. Sign up to guarantee a space in your preferred area!!! *DATES*: January 14 & 15, 2023 *LOCATIONS:* InfoAge: 2201 Marconi Road, Wall Township, NJ Building 9059 (CDL Hackerspace - Formerly IXR) TIME: Saturday START time == 10 A.M. END time == 11PM. Sunday START time == 10 A.M. and END == 5 P.M. *SIGNUP HERE!*: Signup sheet Click HERE <https://docs.google.com/spreadsheets/d/1-CzOmtnbGWwcNc53ewymcAe1Zt5xNTow4cm…> ! Face Masks are required for non-vaccinated people. Vaccinated people have the option to wear masks, but they are highly recommended. *COST:*- $15 per person, PER day. This money goes to InfoAge and CDL. - $25 per night for those wanting to stay overnight (Money goes to InfoAge). Please pay ME upon arrival. Cash or PayPal is acceptable as payment. Ask ahead of time if you need to use a credit card. *OVERNIGHT*: Bring your own pillow, blankets, soap etc. We provide a bed frame and an uncovered mattress. There are showers and a kitchen for your use. - You can pay via PayPal to paypal(a)vcfed.org. or to me via cash or credit card in person. *EQUIPMENT:* - VCF will provide a table and you can use any available electrical outlet. - Bring your own tools, power strips, power cords, and supplies etc. - If you need particular tools that you don't own or particular parts, please post to the list for those going. They may have what you need. Let them know ahead of time. - Let everyone know what project you are working on ahead of time to inspire collaboration. *DRINKS*: You should bring your own. We have a refrigerator in CDL to keep them cold. VCF will buy some water and soft drinks for member use. *FOOD*: *Saturday Night Dinner at 7PM?*: Options: * Brick House Tap and Tavern * MJs * Patrick's Pub * Ottos * Robinson Ale House *Sunday Morning*: Blue Swan Diner *Sunday Afternoon*: Wawa? *PARKING:* Park in the main parking lot, unless you are unloading. Don't park on the lawn. QUESTIONS? PHONE: ( 7 3 2 ) 7 2 2 - 5 0 1 5 EMAIL: repairworkshops AT vcfed DOT org Have fun everyone! ========================================= Jeff Brace VCF National Board Member Chairman & Vice President Vintage Computer Festival East Show-runner VCF Mid-Atlantic Executive Director Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey(a)vcfed.org

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[FS] Really Nice Fully Loaded and Boxed IBM AT with 5153 and 5154 Monitors
by Alexander Jacocks 10 Jan '23

10 Jan '23

All, I just posted this on VC Forum, and wanted to make sure that everyone here saw this listing, as well. Please let me know if you are interested. - Alex https://forum.vcfed.org/index.php?threads/extremely-nice-foully-loaded-ibm-…

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VCF East 2023 Registration Links
by Jeffrey Brace 07 Jan '23

07 Jan '23

In case you missed the previous emails: Exhibitor Registration: https://forms.gle/iKZNPqFPSeobjnau5 Vendor Registration: https://forms.gle/zGsPxCcuDQBXm3fb7 Volunteer Registration: https://forms.gle/UEbiFYvgEiBk9MS27 Speaker Registration: https://forms.gle/yvV311ucBEWXzqpx9 ========================================= Jeff Brace VCF National Board Member Chairman & Vice President Vintage Computer Festival East Showrunner Vintage Computer Federation is a 501c3 charity https://vcfed.org/ <http://www.vcfed.org/> jeffrey(a)vcfed.org

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Re: [vcf-midatlantic] What we can learn from vintage computing
by Jeffrey Jonas 05 Jan '23

05 Jan '23

Bob Jeffway posted: > I co-teach a class at University Of Massachusetts in Amherst > using Bob Applegate's KIM-1 replicas. An interesting choice for sure. Hex keypads & displays are definitely a step-up from toggle switches and individual bits. > We start with machine language programming, then move to an assembler, > and teach all the low-level stuff; address bus, data bus, controls, clock, etc. > and how to interface hardware. Very nice! Ben Eater advocates breadboarding everything yourself, learning every wire along the way: https://www.youtube.com/c/beneater One of my masters' degree pre-reqs was a 68000 lab course with this single board trainer: http://ferretronix.com/tech/sbc/index.html#68k The ROM provided an interactive debugger and a few run-time library calls for print, read, etc. http://ferretronix.com/tech/68k/68k_monitor_notes -- jeff jonas

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Bad bearing in Atlanta (ST-225)
by Neil Cherry 05 Jan '23

05 Jan '23

Michael Evenson of the FlexUsergroup (FuFu) email list (Flex, OS9, OSK, UniFlex) has a drive with a failing bearing. Is there a repair group down in Atlanta are like we have at the museum in Wall? Really like to help him keep going on his emulator. If not does anyone have a ST225 drive they're not using? -- Linux Home Automation Neil Cherry kd2zrq(a)linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies KD2ZRQ

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OS-9!?! :-)
by Herbert Johnson 05 Jan '23

05 Jan '23

> On 1/3/23 10:09, Neil Cherry wrote: >> Dave I think we need to get you a 68000 OS-9 system for the LSSM! Taking >> the Large Scale technologies and putting them into the little scale devices. > > I would absolutely love that. What hardware do you think would be > appropriate? -Dave Mc Guire Maybe 20 years ago, I worked in the Princeton NJ area for a tiny company that produced a PC board imaging scanning system, for PC board component inspection. It used an analog TV camera on an X-Y mount, digitized images, and recognition software trained on other images. Of course it looked for component errors, misplacement, etc. The computer was a Motorola VMEbus 68000 system, running on OS-9 68K. The image processing code, was FORTH. Motorola produced a range of VMEbus 68K systems, as did other companies. But Motorola created the VMEbus. I believe OS-9 68K found a lot of industrial use, it was a bit pricey in hardware and software for home/hobby users. But many hobbyists and business people familiar with SS-50 and OS-9 6809 (and Flex), found their way to OS-9. And i think there was an OS-9 flavor for the Tandy Color Computer (6809) line. Early Sun stuff was 68000 I believe. Unix ran on 68000's. and of course, the Macintosh was 68K before PowerPC. Later in life, I've accumulated some VMEbus cards including various 68000 and 68010 boards and I/O cards and chassis. They are out-of-favor now of course, but I get requests occasionally for replacement boards, not much hobby interest. No software for them. An OS-9 port would not be hard, but too hard for me. To Dave's question. It's a decision in a vintage computing collection, to select industrial equipment, business equipment, or hobby equipment, or the crossovers. People choose what's familiar to them, from whatever domains where they encountered computers they found of interest. "Hardware appropriate"? Depends on your goals. But a 21st cent. SS-50 6809 running NitrOS9, next to a 68000 industrial thingy running something (OS-9, Unix), and a Tandy Color Computer nearby, would be a Motorola trifecta. Add the SWTPC 6800 running Flex on floppy to get something seriously vintage. 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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OS-9!?! :-)
by Herbert Johnson 05 Jan '23

05 Jan '23

> Douglas Crawford wrote: > I'm not sure what those user accomplished with [OS-9], that > would be interesting to hear about if someone wanted to start a thread > on that. Um, "read the fine Internet". Archives of old user group emails, archives of old user-group paper newsletters. It's fine to have conversations; but to "what users accomplished", look at the records, look at the works. In any event, OS-9 and SS-50 systems in the era were sufficiently robust to be used in industrial and business systems. A search for catalogs and conventions sponsored by OS-9 (Microware) using companies will suggest the range of customers and applications. It's from a time before the IBM PC monoculture, when microcomputers of all kinds flourished, and did real work. "Thunder is good, thunder is impressive; but it is lightning that does the work." - attributed to Mark Twain Herb 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 comcast DOT net

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MDD G4 MAC Power supply MOSFET needed
by Sentrytv 04 Jan '23

04 Jan '23

Hello to all you Mac people out there. I’m currently working on a power supply (Samsung P58) for a mirrored G4 Mac that has a bad mosfet W20NM50. Apparently this is no longer manufactured but is available from many Chinese and Korean outfits on eBay. Obviously I don’t want to wait that long to get one or take the chance that they are restamped. So, anyone out there in nj or near by, going to the January Workshop that may have a couple of these? Please feel free to contact me directly if you can help. Thanks Mike Rosen Sent from: My extremely complicated, hand held electronic device.

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