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AT&T UNIX PC 3B1 vs. 7300by billdeg Total messages in this thread: 5 Updated: [ Using an External Terminal ] 10/12/2014 I received some AT&T UNIX PC parts this week from Mike Lee ( http://www.geekmuseum.org ) Specifically he sent me most of a UNIX PC "7300" model. I own a dead "3B1" model, which can be differentiated from the 7300 by it's raised monitor. I could not find any 3B1 images on the web, below is a link to my system's pics. There are plenty of the 7300's on the web. Anyway, I started into diagnosing what was wrong with my system, and his too. I was hoping to be able to merge my dead system with the parts from Mike's and create a working system. Almost... It turns out that the later model of the UNIX PC, the 3B1, has a different power supply than the older 7300 variants. Mike sent me a "middle version" 7300 with 1 MB onboard RAM. He sent me two good power supplies. Unfortunately neither will work on the 3B1, not the same juice. I checked with volt meter, compared with interne">... [ read more ] |
Mattel Electronics Auto Raceby billdeg Total messages in this thread: 1  First Handheld Electronic Game, the 1976 Mattel Electronics Auto Race.
I was playing around with this game and gave it to my kids to mess around with. They were mildly interested, but did not really get it. So much for the first entirely digital handheld electronic game. One had to shift into high gear while the car (represented by a LED light) was at the bottom of the track and steer clear of the on-coming cars (more LED lights). As the player's car makes its way up the track there is less time to react to on-coming cars. To compensate the player downshifts using the GEAR controls to slow the pace of cars. Once back at the bottom of the screen the driver can shift back into a higher gear. The lower the score the better, and the worst score is 99.
512 bytes of program storage (not 512K). The Auto">... [ read more ]
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TRS 80 Model III SN 0019671by billdeg Total messages in this thread: 1  TRS-80 Model III Model 26-1066 with Serial Number 0019671. This unit had two drives with broken drive door latches. From the view of the inside, looks like this machine had little actual use. Click image for larger view.
More Photos
Tandy replaced the early Texas Peripheral drive latches with a better mechanism, but given the drives did not test/perform well, I decided to not to waste good replacement latches on them. Instead I replaced both drives. Both are practically brand new, There is a note with the machine that says the original power supply was replaced in early 2000's.
Not sure if you can tell from my last bat">... [ read more ]
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TRS 80 Model III Exatron Stringy Floppyby billdeg Total messages in this thread: 2 Updated: [ ESF Version 4.1 and hardware photos ] 09/17/2014  TRS 80 Model III Exatron Stringy Floppy, front panel. Click on image for larger view.
 THe Model III Exatron Stringy Floppy is not compatible with the Model 1 version because the model III reserves the memory location the model 1 version needs. For whatever reason, Exatron required that the model III version boot from a wafer. Most wafers have turned to powder at this point so I dare not mess around">... [ read more ]
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Semi-Virtual Diskette (SVD)by billdeg Total messages in this thread: 1  Version 2.4 of the Semi-Virtual Diskette (SVD) was created by a classic computing hobbyist named Eric and could be used on TRS 80 models, Apple II, TI 99/4a, and Heathkit computers to extend a modern PC serial port to emulate a diskette drive. Click image for larger view.
This particular unit had a blown power supply and 7805 voltage regulator when I got it. Fixed. A nice addition for re-creating archived diskettes to the machine in order to build new diskettes. I don't think that Eric still builds or supports this product anymore. Not sure how many were produced.
Website address for support and software:
http://www.thesvd.com/SVD/">... [ read more ]
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Hand-held Calculators and Computerettesby billdeg Total messages in this thread: 1 
The 1978 Toshiba LC-836MN is considered by many authors to be the first hand-held personal assistant / databank, a computer-ish calculator. Click image to view more photos.
I have uploaded new photos into the following directories, most are small handheld calculators with computing abilities, a few games and odds and ends. These are not new to me things but I had been meaning to upload images for some of these for years. more than half of these are from the E Koblentz collection. Each has been tested and cataloged, batteries removed when present. I almost always have at least one handheld computer on my desk to use for day to day use.
AST
Newton
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Teletype as Program Storage for Kim 1by billdeg Total messages in this thread: 2 Updated: [ 470 ohm resistor ?? ] 08/28/2014 Per http://www.kim-1.com/usrman.htm#F24 I am working to set up my KIM to a teletype (not using rs232) using current loop/papertape old school. I have mine wired up now, but have not actually powered on to test. I have what I think is right, but first I want to do more research.... I think it's: application pin T --> Teletype terminal strip connector 6, "what KIM schematic calls the keyboard" U --> 3 "KIM schematic calls the printer" R --> 7 "KIM keyboard return" S --> 4 "printer return" I am basing this on PDP 11 and PDP 8 documentation where (and this works) "transmitted data -" goes to terminal strip connector 6 "transmitted data +" connects to TS 7 "received data -" to TS 3 "received data +" to TS 4 SO, I guess I am wondering if: "printer" in the KIM docs is the same thing as "received data -" in the DEC pdp docs "keyboard" in KIM docs is the same thing as">... [ read more ] |
Rockwell KIM-1 Rev Dby billdeg Total messages in this thread: 5 Updated: [ Rockwell KIM-1 Rev D Photos ] 08/27/2014  Rockwell, MOS or CBM Kim-1? It's a rev D that should be Commodore, but the brand is obscured by a metal plate. There is no date stamp above the serial number that I have seen in another rev D. Perhaps this is one of the KIM-1's from the transition between MOS and Commodore. Or maybe a Rockwell or other OEM Kim-1. But did Rockwell sell rev D's? The date codes of the chips are mostly early 1977, some late 1976 and the layout is the same as other KIMs that I have seen. Note the serial number is PA2079. This same pattern was used by Commodore in later revisions. PA most likely indicates Norristown, Pennsylvania, USA. Click image for larger view.
Here is another rev D, but it does not look much like mine:
">... [ read more ]
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IBM XT 5160 s/n 5462708(5160)by billdeg Total messages in this thread: 1  A few photos of a nice IBM XT model 5160 with 10mb hard drive, CGA display, and AST Six Pak RAM and utility card. Click image for larger view.
 A view with the top cover removed. All components are original. AST made a fortune selling their add-on cards, which were often purchased to expand the system at a lower cost than IBM's expansion cards. The capacity of this 5160 motherboard was 256K, the Six Pak contributes another 384K plus serial and parallel ports.
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Hackers on Planet Earth HOPE Xby billdeg Total messages in this thread: 2 Updated: [ Hearses and Hand-held Calculators ] 08/01/2014  A small crowd gathers around a display terminal transmitting the Edward Snowden and Daniel Ellsberg panel. Every room in the HOPE X convention was tuned in to this historic discussion. Click image to see larger view.
 The Mid-Atlantic Retro Computing Hobbyists club exhibit, "Apple Computer Timeline". Click image for larger view.
More photos">... [ read more ]
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Teletype Reader Controlby billdeg Total messages in this thread: 8 Updated: [ Teletype Reader Control 4915D ] 07/22/2014  Pictured above is a Teletype Model ASR 33 with the cover removed, from a side view angle just behind the line/local/switch. Note keyboard cams in the upper left. This is a standard/stock configuration. Click image for larger version
 Pictured above is a different Teletype Model ASR 33, this time with a Potter & Brumfield tape reader adapter installed. Click image for larger version.
The second teletype pictured is newer that the first (serial number ~100,000 vs. ~400,000).
">... [ read more ]
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Tektronix 5403 Oscilloscope X-Y Artby billdeg Total messages in this thread: 1 Using a synthesizer to generate sounds that will render shapes and pictures on an oscilloscope in X-Y mode... http://youtu.be/O_EyJIlLbGM Here is how I did it. 1. Set 5A48 (in left bay) to 1 volt per division. Display on, channel one output to AC, mode to channel 1. Plug 10x scope into channel 1 2. Set 5A48 (in middle bay) to 1 volt per division. Display off, channel one output to AC, mode to channel 1. Plug 10x scope into channel 1 3. Set 5B31 (in right bay) sec/div to AMPL. Auto trigger 4. Attach probe connector 1 into the left stereo channel, probe connector 2 into the right stereo channel. Attach the probe ends with alligator clips to the individual segmented ends of a 1/4 in stereo jack cable. The other end of the audio cable would be plugged into the headphone jack of the amplifier unit or mixer. The synthesizer is plugged into the mixer like any musical">... [ read more ] |
Cromemco System 1 12v (U2) Repairby billdeg Total messages in this thread: 4 Updated: [ Repairs Completed ] 06/03/2014  Cromemco System 1 LAS1412 12v regulator in power controller, position U2. The system started to smoke while performing disk operation (directory), so I cut power before damage. I did not see any carbon residue. After a more controlled smoke test I found that I could root to the monitor prompt but I had no more 12V to drives, thus could not boot to a disk. Ordered new part. Not sure if the fault was the regulator or something that caused the regulator to over-work, but I could not find any other electrical fault. Click image for larger view.
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PET 2001-8 Internal Cassette Restorationby billdeg Total messages in this thread: 1  Commodore PET 2001-8 internal cassette drive with cover removed. This photo was taken after two repairs were made. First the original belt was removed and replaced using a donor CN2 cassette. Second I repaired the cable that connects to the motherboard. Click image for larger view.
The Commodore CN2 drive belt can be transplanted into the internal cassette drive. It's easy to remove the belt from a CN2 external cassette. To install into the internal cassette just loosen the ... [ read more ]
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