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Lobo Apple II Disk Drive Cloneby billdeg Total messages in this thread: 1  Very early Lobo Apple II 5 1/4" drive clone, with "Santa Barbara" logo. Click image for more pictures
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Replacing toggle switch on Altair 8800aby billdeg Total messages in this thread: 1 The good news is that for about an hour or so I had a 100% functional Altair 8800a..  MITS Altair 8800a closeup of broken A0 toggle switch. It's stuck in the 1 / on position
.. but Dan and I broke the A0 toggle switch during testing. It was bent and it was probably vulnerable to break so it did not take much to snap off. The system still works, but I can't deposit any values into memory that end in a "0" using the toggle switches. If I want to examine what's in 0000h I have to flip all of the toggles up (FFFFh), press "examine", and then "examine next" to get to 0000h. The lack of a functioning A0 toggle does not prevent me from using the system from a terminal or teletype as long as I have a bootstrapping monitor installed. A temporary setback only.
I decided to disassemble">... [ read more ]
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An S-100 Board for an IBM PC keyboardby monahan_z Total messages in this thread: 2 Updated: [ S-100 PC Kbd to ASCII Converter Complete ] 02/13/2010 An S-100 Board to convert IBM PC keyboard data to parallel ASCII Many S-100 users have/had some kind of ASCII style parallel port keyboard attached to their system. The interface was just a simple 8 bit parallel input port with a second port single strobe bit. Most of these keyboards came from old mini computer systems or simple CRT terminals. Today they are now quite difficult to find. If there are any parallel port keyboards on eBAY etc. from Atari systems and the like, they are usually not in ASCII format but instead deliver key press data in X,Y coordinates etc. Today almost all PC systems interface the user via an IBM PC (AT) type keyboard. This is in fact may be the single most lasting effect the IBM PC has had on the PC business in the past 30 years. However the IBM keyboard does not return data to the computer via a parallel port. Instead it does so in a more sophistica">... [ read more ] |
Apple II A2S1-33122by billdeg Total messages in this thread: 3 Updated: [ Source for replacement Apple II ROMs ] 02/04/2010 Recently picked up an Apple II S/N A2S1-rev0.  Apple II Serial Number A2S1-rev0. Click for image larger version.
 The original owner installed a fan into the back of the case.
The ROMS that came with the system are:
ROM D0 missing
ROM D8 missing
ROM E0 3410001
ROM E8 3410002
ROM F0 3410003
ROM F8 C2080M
E0, E8, and F0 are the original integer BASIC ROMs.
As originally received, the system displayed alternating white/black vertical lines with a cursor at the bottom left, when powered on but no Apple">... [ read more ]
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Univac 1219 rescueby billdeg Total messages in this thread: 1 I participated in the recovery of suite of mid-1960's Univac computers and peripherals. These items were sent to the Mid Atlantic Retro Computing Hobbyist museum housed within the InfoAge Science Center pf Wall, New Jersey. I am V.P of this club. Upon seeing the room full of Univac equipment I was shocked at the sheer size and quantity of the computer systems. It was like being in a Doctor No movie. Tape drives, lights, etc. Everything you'd expect from an early 60's bad-guy headquarters. 2 1219-B's 2 1540 Tape Units 3 1532 I/O Console with Teletype (not 33's, something larger) 1 MK-75 Targeting Computer Another I/O station whose name I forget. spare parts galore, hundreds of flip chips and components cables, connectors, etc. misc other items. After going through the truck rental process I drove to Johns Hopkins APL in Clarksville, MD. I went through the whole">... [ read more ] |
PDP 8i sells for $15,000by billdeg Total messages in this thread: 1 Pictures taken during a visit to a nearby hobbyist. This system was later sold to Vulcan Electronics.  The venerable PDP 8/i system
PDP 8i - 4
full-height racks.
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IBM 5160 - unsung heroby billdeg Total messages in this thread: 1 Funny, as much as I use my IBM XT for testing, I never took any pictures of it before.  The empty right-hand drive bay of my IBM 5160 XT computer has been used to test countless floppy disks and hard drives destined for other systems. The reliability of this computer allows me to focus on the drive and any issues that may be related to it, knowing I can count on the computer.
 Rear left view of the IBM 5160 XT computer
 The IBM 5151 Personal Computer Display
IBM Pics">... [ read more ]
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Altair 88-MBL MultBoot Loaderby billdeg Total messages in this thread: 1 I won an Altair 8800 Prom Board with an 88-MBL prom installed. 
Tested. The data loaded into memory matches the code listing in the documentation.
To be continued.">... [ read more ]
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Fido BBS listing node list 6-13-1986by billdeg Total messages in this thread: 1 I found a copy of a fidonet node list on a diskette. This nodelist is not currently on any archive. In the BBS spirit, one used to have to upload files before one could get into the deeper levels of a BBS. Back then I remember thinking, what files do I have that anyone would want? Fido BBS listing as of Friday, June 13, 1986 -- Day number 164 : 201113 FIDONET node list 6/13/1986 ">... [ read more ] |
IBM 5144 Displayby billdeg Total messages in this thread: 1 The IBM 5144 was the first "modern" design display made by IBM.  The IBM 5140 PC Convertible Laptop had a lot of add-on features. One of these was an rear attachment for an external display. Pictured is the 5144 monochrome display.
The IBM 5144 the monochrome display made for the Convertible. There was also a color version. The 5144 pre-dated the PS/2 line VGA monitor style, and had the same angles as the 8514 and other first generation PS/2 VGA monitors.
 The IBM 5140 came with a customizable menu program and IBM DOS 3.2.
More pictures of IBM PC Convertible Model 5140">... [ read more ]
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Commodore IEEE Drive Blink Codesby billdeg Total messages in this thread: 1 This is a copy of text from http://www.6502.org , for my reference, whose source is I assume the owners/repair manual or somewhere else on the web. Disk drive error codes (4040, 8050, 8250, sfd-1001, D9060, D9090) The Commodore disk drives indicated hardware failures detected during boot with a blink code. Here's the meaning from the 8050/8250 service manual: POWER UP DIAGNOSTIC FOR 8050/8250 FLASH CODE On power up, the three LED's on the drive should blink. The drive LED's go off and the center Tri-State LED remains green. The system has a built-in self diagnostic which can be read in the form of a flash code. In the event of a failure, the 3 LED's will blink in a repetitive sequence. The number of blinks between intervals will indicate the possible location of a failure. ERROR INDICATIONS NUMBER OF FLASHES ERROR CAUSE COMPONENT LOCATION 1 Zero Page 6532 UC1,">... [ read more ] |
Fire Destroys Orig. R.E.S.T.O.R.S Homeby billdeg Total messages in this thread: 1 http://www.trentonian.co...4474191.txt HOPEWELL TWP. Windswept flames 50 feet high yesterday destroyed the local barn where computer programming first flourished, beneath an imported stage that was first used at the New York Worlds Fair of 1964. The 50-by-100 foot building on the property of computer pioneer Claude A.R. Kagan, now 85, gained a reputation in the late 60s and 70s as a hangout for misfits from Hopewell Valley High and Princeton kids whom Kagan said he pulled away from pot and turned on to computers. Early members of that first 1967 computer club in New Jersey, known as the RESISTORS, wrote programs in SAM76, Kagans own early computer language, and even wrote a primer about the language, said an ode to Kagan when he was honored as 2007 Hobbyist of the Year by the Amateur Computer Group of New Jersey. ">... [ read more ] |
How to Use PET 2001-8 2nd Cassette Portby billdeg Total messages in this thread: 1 Commodore PET 2001-8's have the built-in cassette player, but many of the internal players no longer work. Here is how to use an external cassette player from a VIC-20 or newer PET: 1. Plug external cassette unit into the port on the far left (facing from the back). The port has slot guides that should match your cassette jack. 2. The 2nd cassette port is assigned the number "2", so the command to access the 2nd cassette drive is LOAD "FILENAME",2 SAVE "FILENAME",2 ..where FILENAME = the file you wish to open. If you have a cassette but you don't know what the name of the program is, you can get a directory by substituting the FILENAME with the * character. Get a pen and write down the file names as the system lists them to your screen. Even a short program will take 30 seconds or more to load be patient. Note that the oldest PET's do not have the ability to i">... [ read more ] |
TRS 80 Model III Drive Replacementby billdeg Total messages in this thread: 1  The TRS 80 Model III with Texas Peripherals 10-5355 drives. The top drive in this unit (drive 1) is not functional so I replaced it.
After testing thoroughly, I determined that the index sensor was bad, I could not verify a formatted disk. I decided to put in a new drive rather than fix it. First I put in an IBM Tandon 100 2A, it worked but it looked funny with the "IBM" logo. I settled instead for a TEC FB-2002-TR000 drive. The two drives look different, but they work.
More pictures">... [ read more ]
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Answer to Trivia Question: What was official Computer of the 1984 Canadian Winter Olympic Team?