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The lost NASA tapes

by billdeg - 07/01/2009
Total messages in this thread: 1
This is an article that illustrates the importance of preserving the skills needed to preserve ancient data from being lost. From Computerworld online: The lost NASA tapes: Restoring lunar images after 40 years in the vault A Mac Pro and 40-year-old tape drives are helping restore the original Lunar Orbiter tapes http://www.comp...12&pageNumber=1 Here are some pictures from an actual Apollo lander computer, courtesy Frank O'Brien from VCF East 3 2006. Apollo Guidence Modules Apollo Guidence Module Closeup 1 Apollo Guidence Module Closeup 2... [ read more ]

Bubble on a 16v 3300 uf

by billdeg - 06/29/2009
Total messages in this thread: 3
Last Post: [ Altair 8800 power supply capacitors ] 06/30/2009
has been restoring an Altair 8800 S/N 220744K. By participating in the restoration process I have learned a whole lot and I am starting to apply this knowledge to this and other projects. For starters, I am going to test every electrical component and compare with another 8800, same model. I want to try to get them both running by comparing and contrasting how they work. This is a good approach for the amateur, if you can find another working system and you know how to use a voltmeter and soldering iron. Anyway, As I was testing the caps in the back by the power supply I found that one of the caps is about to go:
Image of Altair 8800 16V 3300 uf capacitor with a bubble forming on the plus side. It's the o... [ read more ]

VTL-2 for Altair 680b

by billdeg - 07/10/2007
Total messages in this thread: 3
Last Post: [ VTL BASIC for 680b - Working ] 06/25/2009
Just a quick note...I have been working with Grant Stockley to build and test ROMs for VTL-2. I helped test. Grant sent me a copy of the three PROMs needed to load Very Tiny Language 2 (VTL-2). Here is the current status. I put all three PROMs in place. I was not able to boot to BASIC, instead I get various inconsistent results and no "OK" prompt. Sometimes a series of 10 or so " . " characters, scroll down the screen, one per line before the system halts; sometimes just a single letter will appear, sometimes nothing happens at all. There are more details, but that's the long and the short of it. I can't get to the ACIA monitor prompt if all three PROMs are in place. I was able to use the toggle switches to check memory. Working backwards from the end of VTL-2, I found that all of the memory was intact/correct (spot checking a few dozen locations). The program is loading... [ read more ]

Analog Computers 1961

by billdeg - 06/23/2009
Total messages in this thread: 1
The cover of Popular Electronics December 1961, featuring analog computers.
NOTE: You will need to log in (or create an account) to download these articles. In the photo above this General Electric EF-140 uses an audio signal generator to send output indicating a correct answer through a headset. The dials have logarithmic and trigonometric scales, plus squared and reciprocal scales. Best Buys in ED-EL Kits (includes some educational analog computers) by Louis Garner Jr. An Introduction Info Analog Computers by Julian Sienkiewicz Advertisement for Minivac 601 Analog C... [ read more ]

Altair 680b (2nd)

by billdeg - 05/18/2009
Total messages in this thread: 6
Last Post: [ FUA7805 in Q1 on 680 mother bd ] 06/21/2009
Two versions of the Altair 680b. The left unit has the older round toggle switches, the right has the newer flat switches. Click for larger image.
I was lucky enough to get a "new" Altair 680b, very similar to my first one, but with the expansion connector, a 680 cassette card (KSCAR), a 2P/SIO, and two hacked SWTPC MP-M 4K RAM cards attached to a 680 expansion card. To start, I am checking the IC and voltages. I am able to toggle and recall memory within the first 1K, but the ACIA in ROM slot T is not being written to memory (FF00 --). I swapped the ROM and the ACIA (6850) chip into a working system, to verify that the these chips are OK...they are..so.. I started checking voltages and so far I have found a bad voltage regulator and... [ read more ]

Heathkit H-19 Restoration

by billdeg - 06/20/2009
Total messages in this thread: 1
Thank you for Herb Johnson who helped troubleshoot and advise repair strategy I bought an H-19 terminal a while back for parts. The previous owner had started converting this computer into a sort of H-89, with power for disk drives and a cassette port. She/He did not get very far. Voltage regulators on the display control board - OK Power supply controller - bad 12-volt regulator (103). Not needed if we're just reverting to a H-19, but might as well fix if ever in the future someone wants to upgrade this to an H-89 with drives. UA78H12S0 Adjusted the yoke to align the display Serial port is marked "330-337", near the brightness knob. Now it works great, using now for testing systems.... [ read more ]

Another VC Hacking Weekend

by billdeg - 06/15/2009
Total messages in this thread: 1
This time we were put up by Mike Lowen, who hosted the weekend. Pictures: http://sturge...ewen/Oldtech/VCW/ At a minimum,progress was made with the following 2 Heathkit H-89 Computers 1 Heathkit H-19 Terminal 1 Altair 680 - testing VT BASIC 1 Altair 680 - board repair 1 IBM 029 Card Punch Unit - Almost fixed Donner 3500 - Tubes tested and OK Attendees: Herb Johnson, Bill Degnan, Alex Bodnar and Barry Kline, Mike Loewen. Herb Johnson's page from the event: http://www.retro...m/restore/r_loewen.html... [ read more ]

Atari 800 ... portable?

by billdeg - 06/09/2009
Total messages in this thread: 1
Well not exactly. This unit sports a handsome Casemaker travel bag.
The Atari 800 with a Casemaker travel bag. Click image for larger version.
I don't pay much attention to Atari computers on this web site, but I do think that they're a great company. I have a small project involving the restoration of the metal shields that are attached to the underside of the cartridge cover. The shields sometimes detach from the inside lid of the cartridge cover because the system's adhesive foam deteriorates.
Three 16K RAM cards and one 10K ROM card are installed in... [ read more ]

Digital (DEC) PDP 11/05 NC Assembly

by billdeg - 06/09/2009
Total messages in this thread: 21
Last Post: [ Teletype Reader Control 4915D ] 07/22/2014
Ted Nelson speaks quite highly of the Digital PDP 11 series in his book Computer Lib / Dream Machines.
Picture of the PDP 11/05 NC card cage and M9970(in the wrong slot). Click image for hi res version.
The only thing that prevented DEC from launching the PC revolution three years earlier was price, in my opinion. All of the other ingredients were there for a fine PC. The PDP 11/05 was the OEM version of the PDP 11/10, so you find all kinds of variations of this system sometimes paired with the DEC GT40 Graphic Display Terminal. Complete set of Pictures Some notes... 1) Cleaned (enough for now).. got all of the styrofoam peanuts, dust. 2) Started with an [ read more ]

Cataloging ESF wafer library

by billdeg - 03/09/2008
Total messages in this thread: 2
Last Post: [ format wafer in 2nd stringy drive ] 05/29/2009
I am in the middle of cataloging all of my working ESF programs. I have been side-tracked by other projects, but soon enough I'll get through it all. ...a few screen shots taken during testing: http://www.vin...on_stringy_floppy/ I sold my spare Exatron Stringy Floppy drive on Ebay last week. What's next... Using TRS 80 Model 1 1. Implement a method for converting wafer contents to cassette (Users guide has instructions) 2. Implement a method for converting wafer contents to disk The issue with #2; you can't have the expansion unit and the ESF operating at the same time because they use the same expansion port. So what I believe you have to do is set up two TRS 80's and share one cassette drive. The first TRS 80 will have the stringy floppy and the cassette, the 2nd will share the same cassette (using a switch box) player and wi... [ read more ]

Hobbyist Computerized Bulletin Board

by billdeg - 05/21/2009
Total messages in this thread: 1
I have posted a scan of the Nov 1978 Byte Article (page 150) Hobbyist Computerized Bulletin Board by Ward Christensen and Randy Suess This is the important article about the famous CBBS/Chicago BBS - Considered the first home brew BBS. http://vintageco...0ward%20christensen.pdf... [ read more ]

Old Timer's Day at PACS

by billdeg - 04/11/2009
Total messages in this thread: 2
Last Post: [ Slides from Meeting ] 05/17/2009
The Philadelphia Area Computer Society cordially invites the members of MARCH to: "Old Timer's Day" Saturday, May 16th 2009 Super Giant food store Community Center, 2nd Floor 315 York Road Willow Grove, PA 19090 With a special guest appearance by: Bill Degnan from 12 to 1 PM. There will be tables set up for folks to demonstrate their vintage computers after Bill's talk. For further information go to: www.pacsnet.org Please plan to attend, to make this a very special day. Thanks, Ron Kushnier ... [ read more ]

Landenberg Today Article

by billdeg - 05/04/2009
Total messages in this thread: 1
Yours truly is on page 86 http://www.bluetoa.../publication/?m=507&l=1... [ read more ]

Another 5150 Restoration

by billdeg - 04/28/2009
Total messages in this thread: 1
Today I got an IBM 5150 B in the mail. It was absolutely filthy. There was a layer of dirt-turned-crud covering everything. There were playing cards stuffed in the B drive and an old disk in the A drive. The system did not power up. I almost gave up right then, but .. I took out all of the cards (CGA, AST SixPak, IBM floppy drive controller) and then cleaned everything as well as I could. Powered up - fan started, long beep two short beeps (missing/bad display). Ah, it must be one of the cards shorting out the power supply. Correct - It was the display card. I replaced it. Put everything back in to the slots. Powered up - fully functional. I cleaned it to "excellent" condition with a magic eraser, paper towels with soap and water, q-tips for the keyboard and drives. Another computer saved from the dump. ... [ read more ]

Landenberg Hack Weekend

by billdeg - 04/26/2009
Total messages in this thread: 1
Dan R and Bill Dr #3 came to my house this weekend. A lot was accomplished. We worked on an Northstar Horizon and used it to match a 2nd backup drive and controller card for use in another system. IMSAI 8080 - Dan demoed how his system boots to IMSAI BASIC from PROM which can load programs from simulated terminal input, and he demonstrated his modified a lunar lander program to land on autopilot. Altair 8800 We made a copy of the Altair Monitor II using a DOS-based EPROM burner and Dan's IMSAI 8080 for testing it. The monitor is patched to use the Altair SIO-2 controller but we did not quite get either cards on hand running properly. We put the EPROM on a 64K Tanner RAM/ROM card and it appears to work correctly on a front-panel system. I anticipate that we will be able to install on the Altair when it's ready. We also identified and replaced a slew of bad front panel chip... [ read more ]
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