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c e
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unrelated but along the same vein...
c e   1/22/2018 9:36:26 AM
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anyone interested in tinkering with a 1940 RCA 50 kW shortwave transmitter? http://www.cbc.ca/news/canada/new-brunswick/mi-kmaq-transmitter-radio-canada-1.4495286

traneus
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Source for obsolete manuals
traneus   1/17/2018 11:05:10 AM
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The Linda Hall Library in Kansas City, Missouri, USA, specializes in collecting old technical data, including manuals for obsolete equipment.

masher
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Re: Boston Globe delivery
masher   12/21/2017 6:24:56 PM
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Oh I almost forgot, the beast in it's first 1990's software itteration used a IMB 386 style PC to align it on our in house home brew ATE system.   Around 2001 we were just crossing over to 486 and more modern PCs with some factory and service center test still requiring the use of an IBM 386 to keep the beast alive.     Around 2002 timeframe we went to a more modern off the shelf ATE system but for some older government customer who mainly wanted repairs and minor upgrades we were still required to keep the 386/486 PC lines alive.   I wouldn't be surpised if there were still some old 486 model IBM PC's still being used in the Prescott Arizona service center only because there are thousands of this model radio still in use from the early 1990's happily aiding various military and state/local public safety agencies througout the world.

masher
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Re: Boston Globe delivery
masher   12/21/2017 6:12:32 PM
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For me it was a product called the Wulfsberg RT5000, a 29.7 to 960 MHz  fixed wing/helicopter public safety Transceiver with AM/FM  transceiver modes all available in several operating bandwidths, a true do everything cover everything aviation public safety radio at the time. I was on the original design team starting in 1990 designing the transmitter power amplifier section. I left in the last month of 2010 but the product is still selling and in it's same basic analog form factor albiet with some outboard additions thrown in for newer modulation formats such as P25 digital/trunking. The basic analog tansceiver with it's Old Motorola 56000 DSP, 80C51 processors sprinkled all over the major boards, vacum display, TMOS power transistors and a assortment of 1206 and 0805 components and too many to number hand wound low pass filter inductors is still being produced 27 years later. Support, who knows?  When I left in 2011 parts were at times hard to source but still we always managed to scrape the parts up to keep it going for another 5 years. I often wonder who is remaining that has to work on the beast as I liked to call it?

Evariste
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Manager
Re: long tails....
Evariste   12/12/2017 7:13:46 PM
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I started my career working on paging transmitters.  Some of the Chinese customers were still using 25-year-old transmitters and we were still making the same model beause they didn't like retraining their techs.  It made no business sense for us, which is one reason that that company is out of business.  The circuit boards had to be hand-assembled with through-hole parts.  There was an ID code for each transmitter and instead of being stored in a ROM you had to program in the code by cutting out diodes with a pair of dykes.  I had to redesign some analog filters for this transmitter when parts went obsolete.  This was in the day when a 3KHz-cutoff filter would normally be done in a DSP but I was designing analog active Butterworth filters.  Anyway, that was a product that had a long lifetime, and maybe long after I "updated" some of the parts, though by then the era of pagers was fading out. Aerospace designs often have a long life.  I think they were using ferrite-core RAM in the shuttle for a long time. 

David Ashton
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long tails....
David Ashton   12/12/2017 3:21:59 AM
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"And what's the longest-living product that you have ever helped design?"

I got my first training as a radio tech in the grandly named British South Africa Police radio section in the then Rhodesia.  We got some new 40 MHz AM vehicle 2-way radios from a company called Emcom in New Zealand.  The modulation stage (for AM so it was just an audio amp with power output comparable with the RF output) had a pair of power transistors driving a centre-tapped transformer.  There was a fairly simple line-up procedure to set and balance the quiescent currents in these transistors, but it involved getting your meter probes into two tiny holes in a 9-pin socket in the corner of the (very crowded) board.  So I made a tester with two small and old but identical meters that measured the currents simultaneously, and while I was about it put in a switch to measure some other parameters - RSSI, battery voltage and the like, that were on other pins.  It connected to the radio via a 9-pin plug on a cable, with a long bolt as a handle.  I proudly labelled it "ASH'S EMCOM TESTER".  It was incredibly useful and was always getting borrowed by other techs.

Over ten years later I went back there to visit a friend and there on a bench was my Emcom tester.  My friend said there were still a few Emcoms around and the tester was still used regularly.  I guess ten years is not a lot but for a quick and dirty tester it's pretty good.

traneus
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LaTeX unchanging file format
traneus   12/11/2017 8:31:39 PM
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If you really need a formatted document to last a long time, use the open-source text formatter LaTeX, and don't use a word processor. LaTeX (created by Leslie Lamport) is built on TeX (created by Donald Knuth to format his books "The Art of Computer Programming" so his books would never go obsolete). These are standard in mathematics, physics, and engineering for writing journal articles, and are specifically intended to never change. You write source code in plain text, and then run LaTeX to format your paper. Keep both source and formatted versions.

traneus
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notebooks and diaries
traneus   12/11/2017 8:14:49 PM
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Decades ago, I got in the habit of keeping comprehensive unofficial informal plain-text diary files, indexed via HTML files. These diary files are not laboratory or project notebooks, and are not offical formal documentation either. Notebooks are intended to be permanently unalterable once written, for future use in patent lawsuits. My diary files are editable anytime by me, and record everything I think about for a project. If it's worth scrawling on the back of an envelope, it's worth writing up in a diary file. I number the diary files sequentially, with an unchanging three-letter prefix and four digits of numbers incrementing for each new diary file. One HTML index file links to the diary files sequentially by number. Each project gets its own HTML file linking to diary and other files relevant to particular projects. Result: instant internal HTML site of all my work for the company. I put all the files into one directory or folder. The files are organized through the HTML files, not through a directory structure. This means that one file can appear in more than one place in the organization as seen by a web browser. No subdirectories means no searching subdirectories for files. When I need to copy a file, I use the web browser to verify the filename and the command-like copy command to do the copying. In my last twelve years of working, I created 2638 diary text files at work. Since retiring in March of 2010, I have created 1459 text files at home so far.

U. Dreher
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Product longevity
U. Dreher   12/11/2017 6:53:38 PM
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I've created some products that lastet much longer than initially expected: - An individual industrial automation project that was operated from 1991 to 2008 (when the business unit, excluding this installation) was sold.The installation itself was built around 1977, so some parts were 30+ years when it went out of operation. - Some measurement unit was originally developed for a single project - 10 units (plus 2 spares).It ended up as the only system applicable for the task - resulting in 3000+ units sold during 20+ years. Plus some supporting products that sold in the hundredsWhen the microcontroller used was no longer available, my ex-employer decided to go for something "totally new" (and a bit overengineered). We'll see whether this new system will also have a production life of 20+ years. - Another system (same microcontroller) shared about the same fate: 20+ years of production.They went for something "super-duper" - until now nothing is available :) - There are more examples of this kind:Do it right the first time and start to wonder: one solution I kindly considered "inferior" is regarded the "reference solution" these days :(

elizabethsimon
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Re: Save long-lasting documents in plain ASCII text
elizabethsimon   12/11/2017 6:33:59 PM
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The company I work for used to have hard-copy project notebooks. They've all been scanned to pdf. I'm not sure that this is an improvement. And I sincerely hope that the old paper copies are securly stored somewhere.... The newer scans with OCR aren't too bad but the older ones are impossible to search.

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