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2019-05-13 Distractions of Modern Technology
Posted by Accutron  


Dayton Hamvention's third year in The Great Xenia Mud Flats starts this Friday. As usual we will be selling a wide range of technological inventory, including vintage test equipment, calculators, computers, video games, electronic components, technical books and other various and sundry items. We can be found in our normal location at the exact geographical center of Hamvention, outdoor flea market spaces 7414-7417 and 7514-7517.

2019 Hamvention Program (PDF)

We've had a very busy year thus far, and quite a large backlog of new items for the museum have accumulated in the interim. We are hoping to have most of these new devices documented and added to the website over the next few months.

2018-10-23 October Surprise
Posted by Accutron  


Another random assortment of new devices have been added to the museum: the Pickett N3-T power log exponential slide rule, a Western Electric 2N110 point contact transistor and a scarce Western Electric acrylic key tag which contains two uncompleted 10-pin monolithic ICs.

2018-07-23 Gunpowder, Dynamite & Whisky
Posted by Accutron  


We have added several completely unrelated items to the museum: the collectible and sought-after APF Mark 55 RPN scientific calculator, two UNIVAC circuit cards believed to be from the CP-642 military computer, and a very early Westinghouse Style 35241 Precision Wattmeter.

Special thanks to Mark Greenia for donating the UNIVAC circuit cards.

2018-05-21 Dog Days
Posted by Accutron  


Dayton Hamvention's second year in Xenia has come and gone. Although the mud situation was somewhat ameliorated by an insufficient application of pulverized asphalt, the rain was as persistent as it was in 2017, and made its annual encouragement to move Hamvention to a different time of year.

Despite DARA's best efforts to contain and starve us, we had another great year of transactions. Some of our more interesting new items include a rare and ancient Westinghouse Precision Wattmeter, countless ICs and vacuum tubes, and a truly staggering number of vintage calculators, including a rare APF Mark 55 RPN scientific calculator. As usual, we will be adding many of these new items to our museum in the coming months.

2018-05-13 That's Not a Slide Rule
Posted by Accutron  


After months of preparation, we are finally approaching Dayton Hamvention 2018. We will once again have our huge selection of vintage computers, calculators, test equipment, typewriters, video games, scientific instruments, electronic components, technical books and many other items available for purchase. Our booth can be found in the same location as last year: outdoor flea market spaces 7414-7419 and 7514-7519, Hamvention's exact geographical center.

2018 Hamvention Program (PDF)

Despite the lengthy behind-the-scenes buildup to Hamvention, we have added a few interesting artifacts to the museum since our last update. The newest additions to the museum are a Casio Root 121-A electronic calculator, and two different versions of the Pickett N1010-ES slide rule: the standard 10" model, and the tremendously oversized classroom instruction version, measuring four feet in length.

2018-02-14 Masters of Science Nonfiction
Posted by Accutron  


We have procured an example of the Knowm BS-AF-W, the world's first commercially available memristor. Although the BS-AF-W is neither old nor a true digital device, its preordained historical importance and potential significance to the computing industry have earned it a place in our Digital Integrated Circuits exhibit.

In addition to this uncharacteristically modern device, we have recently documented a number of more traditional items as well: a Sama & Etani Model 600 Science Master slide rule, General Electric 2N1086 NPN transistor and a rare key tag from Western Electric's Laureldale plant, consisting of a late production 2N559 transistor entombed in a triangle of clear acrylic.

2018-01-19 Squaring the Circle
Posted by Accutron  


Just in time to supplant our last great quest for arcane knowledge, we have obtained two different part numbers of a newly discovered and completely unidentified type of Western Electric ICP, the F56976 and F56980. These devices resemble the 'conventional' ICPs developed for the Nike-X program, but have 16 pins arranged in a square configuration. In addition to these unique ICs, two new Western Electric transistors have been added to the Discrete Semiconductors exhibit: the rare 3N22 tetrode transistor and the 7B alloy junction transistor.

Taking a brief pause from Western Electric's offerings, three new items have been added to the Slide Rules exhibit: the Dargue Brothers Simplon SR-10 Bilateral, ESCO 6002 and Pickett N200-ES.

2017-12-21 Crystal Unit, Amplifying
Posted by Accutron  


We have added three new Western Electric germanium alloy junction power transistors to the Discrete Semiconductors exhibit: the 2N66, GA-53242 and 9A. Both the 2N66 and GA-53242 are close relatives of the recently added GA-52830, sharing similar intermediate-power characteristics and a proprietary canister outline derived from the original Bell Telephone Labs M1777 experimental alloy junction transistor. The 9A is a later device, rated at a substantially increased 30W dissipation. We have also obtained an example of the heretofore undocumented Bell Telephone Labs A-2277, a developmental transistor in a TO-38 package.

In addition to these affiliated devices, an IBM ESC (374275) SMS card with a dozen TI-manufactured IBM Type 033 germanium alloy junction transistors has been added to the Logic & Memory Circuits exhibit.

2017-12-02 The Grand Correction
Posted by Accutron  


For nearly 10 years, we have been attempting to research the history of the so-called Western Electric SAGE hybrid logic ICs, part number series GF401xx and 112946xx. Although the Smithsonian had long ago published an anecdote which claims these devices are from the "processor of the SAGE system", this statement never really matched the reality of the AN/FSQ-7 Central Computer System, a tremendously large tube-based machine built by IBM. After years of dead-end research and much speculation, the true origin of these devices has finally been discovered. They are discrete logic Integrated Circuit Packages (ICPs) developed for the experimental Bell/UNIVAC DPS-1 and DPS-2 defense computers. The DPS-1 and DPS-2 were incredibly powerful real-time multiprocessor supercomputers used to guide the operations of the Nike-X and Sentinel anti-ballistic missile systems. The article for these devices has been rewritten accordingly. We would like to give special thanks to retired UNIVAC component engineer Larry Bolton for his assistance in this research effort.

In addition to this important discovery, we have added a number of new items to the museum. Two early power transistors have been added to the Discrete Semiconductors exhibit: the extremely rare Western Electric GA52830 development type and the uncharacterized Tung-Sol TS-1453. We have also added a Post Versalog 1460 to the Slide Rules exhibit. However, the most interesting new addition is a Western Electric 1A Memory Card, a permanent magnet twistor ROM from a Bell #1 Electronic Switching System.

2017-08-23 Totality
Posted by Accutron  


We have just returned from Sparta, Tennessee, a prime viewing location for the Great American Eclipse. Our site was a gravel turnaround along Rt. 136, about 350m north of the eclipse centerline. There were a few puffy clouds that gave us some concern, but the sky was completely clear for the main event. I managed to capture sunspots right after C1, and I got some good photos of totality, complete with streamers and prominences. I also discovered that autofocus is not fond of the diamond ring effect. The photographs were captured freehand with my Canon Powershot SX530HS, and I used a piece of gold-plated #12 welding glass as a filter during the partial phase. We experienced 2m 39.4s of totality, only a couple seconds shy of the absolute maximum at Hopkinsville, Kentucky.

Beyond the eclipse itself, the most striking feature of the event was the complete shutdown of everything else near and during totality. All of the traffic on the nearby freeway just stopped, and it grew completely silent.

2017-07-05 Deposed Ruler
Posted by Accutron  


We are pleased to announce the addition of our new Slide Rules exhibit, which currently includes over a dozen devices from a range of different manufacturers. Prior to the introduction of the handheld scientific calculator in 1972, slide rules were the only portable calculation device capable of performing complex functions, making them an essential tool for scientists and engineers. Although slide rule production ceased over 40 years ago, they remain useful calculating devices with a significant user base.

2017-06-14 Additions
Posted by Accutron  


Two new Mechanical Calculators have been added to the museum: a Smith-Corona Marchant 700-XN electric ten-key adding machine from the early 1970s, and the Paul Bruning Resulta-9, a tiny rotary disc adding machine with direct subtraction. We have also documented two new optoelectronic devices: the National Semiconductors NSL-881 silicon photodiode, and a rare Integrated Photomatrix IPL4064 64x1 photodiode array.

2017-05-30 A Clockwork Grey
Posted by Accutron  


A number of new items have been added to the museum, among them our newly acquired MITE AN/UGC-41 military teletypewriter. The UGC-41 has an incredibly compact and elaborate teleprinter mechanism which resembles both a brass clock movement and a car engine.

Other recent additions include the Data I/O 29B Universal Programmer, Lear Siegler ADM-5 dumb terminal, Fairchild Imaging CCD143A linear CCD image sensor, Hewlett-Packard 1990-0311 alphanumeric LED display, Bomac USN-CBNQ-6024 high power ATR cell, and the General Electric NE-30 and NE-40 neon glow lamps.

2017-05-21 Jaynestown
Posted by Accutron  


Dayton Hamvention has once again reached its conclusion. Despite the fact that the flea market transformed itself into a disgusting swamp of sentient, prehensile mud by noon on Saturday, we managed to purchase a number of impressive new items for the museum. Particularly noteworthy finds include a MITE AN/UGC-41 compact teletypewriter, several new pieces of HP test equipment, a Dana 8010B Electronic Counter and a number of unusual vacuum tubes. Many of these new devices will be added to the museum in the upcoming weeks.

We would also like to give special thanks to LHF (James), who traveled all the way from China and attended Hamvention specifically to meet us and donate some fantastically rare LED displays.

2017-05-12 The New Nexus of Awesome
Posted by Accutron  


Dayton Hamvention 2017 starts next Friday in its new venue at the Greene County Fairgrounds & Expo Center in Xenia, Ohio. Our booth is located at Hamvention's exact geographical center, spaces 7414-7419 and 7514-7519 in the west section of the main flea market area. Inventory is even larger than it was last year, with a massive quantity of computers, calculators, electronic components, test equipment, typewriters, scientific apparatus, video games, technical books and other items too numerous to mention.

2017 Hamvention Program (PDF)

Amidst the frenzied pitch of Hamvention preperations, we have completed quality control updates to the Diodes, Triodes, Tetrodes & Pentodes, Spark Gap Tubes, Trigger Tubes & Passives and Detection & Imaging Tubes exhibits, and have also added several new devices to other exhibits. Among these new additions are a Victor 19-4461S desktop calculator and two gas discharge glow lamps: the General Electric AR-1 argon-nitrogen UV glow lamp, and the Melz TH-20, a Soviet analogue of the General Electric NE-34 neon glow lamp.

2017-05-03 Modem of Death
Posted by Accutron  


We have added two early laptops to the Digital Computer Equipment exhibit: the NEC PC-8201a and Epson PX-8 Geneva. In addition to these machines, an entry has been added for the Bell System Dataphone 9600, the world's deadliest modem. Weighing over 20kg, one might assume its preferred method of killing was blunt force trauma, but a Dataphone 9600 did in fact poison a pregnant woman and her unborn child in 1983.

Along with these new entries, most of the photographs in the Diodes, Triodes, Tetrodes & Pentodes and Spark Gap Tubes, Trigger Tubes & Passives exhibits have been replaced, along with the addition of several new devices.

2017-04-15 The Typing of the Old
Posted by Accutron  


The new Typewriters exhibit is starting to look like an actual exhibit. There are now articles for the IBM Model B Executive, IBM Selectric, IBM Personal Wheelwriter 25, Olivetti Lettera 32 and Lettera 33, Olympia SM7 DeLuxe and Remington SR-101. We have also added new articles for the Burroughs Cash Machine, Mostek MK5017BA clock controller and the exceedingly rare Proton KIPD73A, a Soviet-manufactured green LED prototype in an unusual 12x12mm package.

2017-03-24 Shoot the Core
Posted by Accutron  


We have added a number of interesting new items, mostly from a recent equipment donation:

- 2L101B, a primitive silicon carbide LED of Soviet manufacture.
- Allen Systems FX-97 single-board computer.
- Applied Microsystems EM-188 8080/8085 diagnostic emulator.
- Burroughs Portable Adding Machine, a motorized variant with direct subtraction.
- Burroughs SD-11-B-1000-635 sphericular optic display, a rare variant of the SD-11 with black digits on an illuminated background.
- D-G Electronic Developments Super 89 CPU card with two Heath/Zenith Z-89 I/O cards.
- Futaba DM-20 and Iseden DP89A VFD displays.
- Smith-Corona Marchant 10095-F calculator memory PCA with a highly visible TDK EM-2985 432-bit magnetic core memory plane.

In addition to these items, we have started building a new Typewriters exhibit.

2017-03-15 Integrated
Posted by Accutron  


In the past week, the Digital Integrated Circuits exhibit has received the same treatment as other recently rehabilitated sections, with over 100 new photographs, a number of new IC devices and other content improvements. We have also added four calculators from the 1970s to the Electronic Calculators exhibit: the Commodore US-1, Eiko Unitrex 1200, Victor Comptometer 83-1421 and the matchbox-sized Casio Micro-Mini M-800.

2017-03-07 Restoration
Posted by Accutron  


Our readers may have noticed some significant changes here recently. Three weeks ago, we migrated to new server hardware, and we are in the process of refurbishing the content of the entire website. Ultimately, every photograph which does not meet modern standards will be replaced. Many new items will be added, and a few will be removed, to reflect the current contents of our collection. This process is already well underway; all entries in Mechanical Calculators, Electronic Calculators, Logic & Memory Circuits, Integrated Optoelectronics, Glow Transfer Counting Tubes, Beam Switching Tubes, Discrete Semiconductors, Discrete Optoelectronics and Microwave Amplifier & Oscillator Tubes have been completely updated, and include about 60 new items in total. These new and refurbished entries can be easily identified by their larger thumbnails and non-shitty photographs.

The most important new entry in this ongoing update is a highly noteworthy Hewlett-Packard 9820A programmable desktop calculator, used internally at HP Loveland. The key-per-function 9820A is the direct predecessor of the powerful 9825A, and utilizes an earlier version of the HPL programming language. The 9820A CPU is a serialized adaptation of HP's early 16-bit minicomputer architecture, condensed into 128 TTL ICs. 98x0 series machines are the first computational instruments developed by HP which incorporate either semiconductor RAM or LED technology; the 9820A utilizes Intel 1103 1kbit dynamic RAM and features an impressive 16-character alphanumeric readout constructed from four horizontally stacked HP 5082-7101 LED displays.

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