- vcf-midatlantic - lists.vcfed.org

Re: Joe O's X-Y Display Problem
by SVCatITC＠aol.com 04 Feb '17

04 Feb '17

Hi Joe; I will be at the workshop next weekend. Is the Vectrex something that can be transported, and can you come to the workshop in order to explore your problem? Being a hardware guy and interfacing a lot of exotic stuff in my main job, I could have a go at your problem. I'll need to know the SCELBI output signal configuration and wether we can generate up a synched time base for the X axis. We can discuss offline if you like. (I'm the Newbe working on the EAI TR20) Bill Inderrieden In a message dated 2/4/2017 12:00:39 P.M. Eastern Standard Time, vcf-midatlantic-request(a)lists.vintagecomputerfederation.org writes: Message: 1 Date: Fri, 03 Feb 2017 17:26:45 +0000 From: Joseph Oprysko <joprysko1(a)gmail.com> To: vcf-midatlantic <vcf-midatlantic(a)lists.vintagecomputerfederation.org> Subject: Re: [vcf-midatlantic] SCELBI Oscilloscope/Keyboard Interface Updates Message-ID: <CAPXecpCwDnu2ASSE73QfJmO_6q8WzE5RKD9Cd0ddLnkU=wDv5A(a)mail.gmail.com> Content-Type: text/plain; charset=UTF-8 Question, while I know the original display was an Oscillscope, would other X-Y displays work do you think? I'm asking as most scopes have relatively small screens. But the Vectrex game console has a 9" X-Y display. While I know modifications would be needed to accept the input, if it's something you may be interested in trying, I have 2 Vectrex systems, and would be willing to use one for that if you think we could make it work. Joseph Oprysko.

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Re: [vcf-midatlantic] SCELBI Oscilloscope/Keyboard Interface Updates
by Mike Willegal 04 Feb '17

04 Feb '17

Hi Joseph, I don’t know much, if anything about "X-Y” displays and how they may differ from a typical scopes. Because I’m only going to 20x5, the scope screen is actually plenty big enough. Here are a few details on the issues I hope to improve upon over the next couple of months. The scope interface has three outputs. Two are the X-Y vectors each of which is a voltage value offset. The third is a blanking signal. First problem is that my Tektronics 465 isn’t responding fast enough to the blanking signal. There are some limitations in the 465 blanking input, in that it’s capacitor coupled, and along a with resistor in the scope interface blanking circuit it is creating your classic RC time constant delay. I’m going to see if I can reduce a key resistor value a bit in order to reduce this effect or find another way to drive the input a bit harder. The second issue is that the analog board op amp circuit isn’t really calibrated correctly. The design uses an op-amp integrator scheme to “paint” the vectors on the screen. When the circuit is reset to top left, in order to repaint the page, the op-amp outputs drift a bit after that before they “settle down”. I haven’t looked into this in detail, but I’m pretty sure that I can fix this with some resistor value tweaks to the op-amp integrator circuits. regards, Mike Willegal

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Full VCF East schedule
by Evan Koblentz 04 Feb '17

04 Feb '17

Subject to change. :) http://vcfed.org/wp/festivals/vintage-computer-festival-east/vcf-east-sched… ________________________________ Evan Koblentz, director Vintage Computer Federation a 501(c)3 educational non-profit evan(a)vcfed.org (646) 546-9999 www.vcfed.org facebook.com/vcfederation twitter.com/vcfederation

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ONE MORE class needed for Friday 3/31
by Evan Koblentz 04 Feb '17

04 Feb '17

We have one last 60-minute spot to fill for the Friday classes at VCF East. Any topic is fair game if it has wide appeal and makes people into better vintage computing hobbyists.

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Well this is awesome
by Evan Koblentz 04 Feb '17

04 Feb '17

Ethan Dicks is going to give a VCF East Friday class about 3-D printing controlled by 8-bit computers. ________________________________ Evan Koblentz, director Vintage Computer Federation a 501(c)3 educational non-profit evan(a)vcfed.org (646) 546-9999 www.vcfed.org facebook.com/vcfederation twitter.com/vcfederation

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vintage comms days
by william degnan 03 Feb '17

03 Feb '17

I propose that we pick a day and time each week were persons turn on their vintage computing systems that can receive outside communications via dial up, telnet or, other networking. I think keeping a BBS or VAX machine up and running all of the time is tough, but if there is a window where you know that's when people kind of expect it, it'll be more managable...Do I hear a second? We can use the vcforum to post that week's list of who is online and when. Basically a sticky thread where people post the URL or IP address, phone number, etc and technical details to help others make the connection, hours of operation. I can help assign subdomains, etc if anyone needs networking assistance. For example I have alpha2100.vintagecomputer.net assigned to my Alpha here in my basement, but I don't run it 24/7, but I would be willing to schedule to turn it on on a known schedule to make it worth doing. This way I can be there to supervise / troubleshoot. This Friday night (tomorrow)I have to watch the kids, so once they're in bed, say 9PM, I could run a few systems until about midnight to help kick things off. It might be fun to see how many systems a person can hit, catch the flag style. Maybe we could make some sort of challenge of it. Send an email from one or download a file. Just for fun. Bill

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VCF East lodging @ InfoAge
by Evan Koblentz 03 Feb '17

03 Feb '17

Everyone, As most of you know, InfoAge now has a dorm facility. A few people asked Jeff B. and I about the process for reserving spaces there during VCF East. We are developing that process now, and we'll send details to the relevant people (exhibitors, Friday teachers, volunteers) after the March 1st exhibit registration deadline. ________________________________ Evan Koblentz, director Vintage Computer Federation a 501(c)3 educational non-profit evan(a)vcfed.org (646) 546-9999 www.vcfed.org facebook.com/vcfederation twitter.com/vcfederation

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SCELBI Oscilloscope/Keyboard Interface Updates
by Mike Willegal 03 Feb '17

03 Feb '17

I've been busy getting ready for the upcoming VCF east event and I'm really excited about what I'll be able to show this year. I'll show a working SCELBI 8B connected to a oscilloscope and keyboard which are used as a terminal. A cassette tape interface is used as mass storage. It will be running the vintage game, Star Shooter and SCELBI's original integrated development environment (MEA), which dates back to 1975. The SCELBI can natively assemble and run Star Shooter from source code and I'll be able to demonstrate that, as well. The hardware is all reproduction stuff, as fully functional, original SCELBI 8Bs don't exist. The oscilloscope interface has been a particularly challenging project. There is only one known set of original SCELBI oscilloscope and keyboard interfaces. These are in storage at the CHM in California. I only had partial schematics, some excellent photos that Jack Rubin took of the original interfaces during a visit to the CHM, and a few notes in some documentation of related hardware and software. As far as we know, the original oscilloscope driver software and documentation has been lost. I've had to reconstruct the software by reverse engineering MEA's interface to it, along with gleaning a few hints in some surviving documentation that refers to the oscilloscope interface. I now have the hardware and software working. Before VCF, I'm looking to tweak the oscilloscope analog interface board to see if I can improve the quality 0f the oscilloscope display output, as, at the moment, though it's usable, it is quite bad when connected to my Tektronix 465. In order to more easily reproduce the Oscilloscope/Keyboard interface software, I updated my Macintosh OS/X SCELBI application to support those interfaces. The revised application is now available on Apple's app store for $5. I still have version 2.7 (without oscilloscope/keyboard support) available for free download from my website:http://www.willegal.net/scelbi/scelbiapp.html <http://www.willegal.net/scelbi/scelbiapp.html>. I'm asking a little money for the latest version of the app, in order to help cover the cost of Apple Developer Membership, which is necessary in order to complete development of an IOS version, which I would like to do when I find time. enjoy, Mike Willegal

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1980's Sony console TV on CL in MD
by Matt Patoray 03 Feb '17

03 Feb '17

I know a lot of you are looking for older televisions for your vintage computer systems and game consoles. This appears to be a nice condition26" Trinitron from the 1980's. http://baltimore.craigslist.org/ele/5949413880.html Sent from my iPhone

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Urgent update -- exhibit registration
by Evan Koblentz 03 Feb '17

03 Feb '17

VCF East exhibit registration is 2/3rds full. Please register your exhibits soon. Don't worry if all the details are not settled; you can always change them later. We absolutely do not want to turn away anyone, whether you're a VCF East veteran or a newcomer. But when it's full, it's full.

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