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CorData Technologies, Inc. Cordata PPC

by billdeg - 11/24/2007
Total messages in this thread: 3
Last Post: [ Next steps ] 08/26/2012
Here's a rare one...The 1985 CorData Technologies, Inc. cordata PPC computer. The logo on the machine looks similar to the Corona Data Systems' logo, but there's no reference to this model within the Corona catalog. Corona is kind of close to Cordata...Maybe they changed their name late in the game? Pics... [ read more ]

Cybernetic Systems Inc. Mathiputer

by billdeg - 08/10/2012
Total messages in this thread: 2
Last Post: [ Mathiputer Diagnostics ] 08/26/2012
The 1975 Cybernetic Systems, Inc Mathiputer. Click image for larger view.
This device is intended to instruct children on basic math skills. Not functional, needs to be cleaned and tested. more to come.... [ read more ]

TRS 80 Model 4P Repair

by billdeg - 08/12/2012
Total messages in this thread: 1
This is a program I use to test RAM on a TRS 80 Model 4 / 4P. It will id whether you have 64K or 128K and run through a test pattern on the screen to test video RAM as well. I forget the company who made it. Note the "128K" in the upper right corner.
I learned something while repairing a customer's two TRS 80 Model 4P computers. If you have 128K installed and the system does not boot (gives you CRC error during POST of the OS disk), try removing the back 64K RAM (remember to move the jumper back to 64K mode) before you assume it's the disk drive. There have been times when I thought the CRC error was always due to disk drive not being able to load the OS, when it was actually the RAM in error. It's a lot easier to find and replace a bad RAM chip, even if you have to do it one at... [ read more ]

MITS Altair 8800 Power Supply

by billdeg - 08/03/2012
Total messages in this thread: 1
Pictured is a MITS accessory box. No I do not have original MITS power supplies for sale or otherwise.
ALTAIR 8800 original power supply specifications (at the end): (From Dan Roganti [CORRECTED]) T1 transformer Output = 8VAC, 8A This is used to power the TTL logic on the cards in the backplane(+5V). It was very underpowered when many of the slots were populated with cards. T2 transformer (dual output) : This is just a strange part just so they can have a separate 8VAC power supply. This is a "nice-to-have" part but it's entirely unnecessary. Because the Front Panel can't operate without power on the CPU and the CPU can't operate without power on the Front Panel. They just had some unwarrant... [ read more ]

Hewlett Packard 9835B

by billdeg - 07/30/2012
Total messages in this thread: 2
Last Post: [ Testing the HP 9835B ] 08/03/2012
HP Hewlett Packard 9835B
The Hewlett Packard 9835B computer. Click image for larger view.
Untested. More to come. pics ... [ read more ]

Hope 9 - July 13-15 2012

by billdeg - 07/16/2012
Total messages in this thread: 2
Last Post: [ History of Portable Hacks Talk at HOPE 9 ] 08/01/2012
Mimeo Apple 1
The MidAtlantic Retro Computing Hobbyists exhibited single board computers and trainers at the 2012 HOPE 9 convention in NYC July 13-15. Among the systems exhibited was this replica Apple 1 computer. Click image for larger view.
HOPE 9 Mid Atlantic Retro Computing Hobbyists Exhibit
Here's Jeff telling tales of computing days past to an interested booth visitor. Jeff helped man the exhibit booth for 12 hours at a time, the club owes a lot to him for sharing his knowledge and his dedication to the club. Click image for larger view.
[ read more ]

PERQ System F Workstation Computer

by billdeg - 07/30/2012
Total messages in this thread: 1
Three Rivers Computer PERQ System F Workstation
The PERQ System F workstation computer is I believe the first commercial workstation, if you don't include the Xerox Alto.
She's filthy and missing the keyboard but this is quite rare. pics... [ read more ]

Tandy TRS 80 Model 16B

by billdeg - 07/30/2012
Total messages in this thread: 1
TRS 80 Model 16B
Here is a TRS 80 Model 16B, capable of running both Model II / 12's Z80 software and Motorola 68000 XENIX.
Ran a quick test. Lit up the RIFA cap, but I noticed that the system flashed the expected request for a boot disk. Should be restorable. Keyboard status unknown. pics... [ read more ]

Digital VT-103

by billdeg - 07/30/2012
Total messages in this thread: 1
Digital VT 103
Digital VT-103 Terminal with dual cassette drives.
So far I have downloaded the manual, more to come. More Pics... [ read more ]

Diagnosing Error Codes Franklin ACE

by billdeg - 06/05/2012
Total messages in this thread: 3
Last Post: [ Franklin ACE RAM - MK4315N ] 07/30/2012
The Franklin ACE 1200 computer was an Apple II clone. This system has the version 2.3 ROMs. Click image for larger view.
This is the persistent error code that appears on the screen when attempting to boot an Apple II diskette in drive 1.
NEXT: Determine what the error codes mean, and repair. I am guessing I have bad RAM, 3715 could be a RAM memory address, the other codes probably represent diagnostic values that explain the error, the pointer or stack value at the time of the error, or something like that. We'll see. Here is a link to the Apple Monitor program. The Franklin was cloned from the Appl... [ read more ]

ADDS Regent 20

by billdeg - 07/30/2012
Total messages in this thread: 1
ADDS Regent 20 Terminal
This is an ADDS Regent 20 terminal, the only one I have seen with no numeric keypad. This terminal can be set for current loop or RS232 operation. Click on image for larger view.
This guy needs some serious cleaning but it actually powers up and displays a prompt. More to come. Pics... [ read more ]

ME1702a EPROM Programmer

by billdeg - 07/19/2012
Total messages in this thread: 1
Built by a friend from the kit, I am now the proud owner of a ME1702a ePROM programmer unit. Martin Eberhard did a spectacular job on this device. I insisted on using an original 70's ZIF socket, which needed a squirt of DeoxIT, but other than that it worked perfectly the first time. Now what to program, what to program???? Next I plan to put MINOL on 7 1702a's, see how that goes.... [ read more ]

Adventure!

by billdeg - 08/19/2010
Total messages in this thread: 3
Last Post: [ Log Dump from Adventure Play ] 07/18/2012
This screen shot shows the use of Digital's OS-8 to enter commands. The first command demonstrates how to load BASIC. The second command, "RUN RKB0:ADVENT", loads and runs Adventure! This and the images to follow are photos taken while running on a PDP 8/e computer using a VT 52 display. That's me in the screen reflection.
Opening credits screen of Adventure!
Adventure! is probably the most famous "interactive fiction" program (text adventure game) written for a computer. Adventure was originally written for the PDP 8 computer, I believe the PDP 8e, but I am not 100% sure about that. The whole interactive fiction genre has received a lot... [ read more ]

Two New S-100 Boards

by monahan_z - 07/09/2012
Total messages in this thread: 1
For those interested in S-100 Bus systems and corresponding CPM software, Andrew Lynch & I (John Monahan) have just finished constructing a second prototype of an S-100 Bus video board capable of SVAG video resolution. For those interesting in a better S-100 video display you might want to take a look at this board. It is capable of displaying a very crisp 100 characters per line display. It is based on the LAVA-10 video chip set. This is a Xilinx Spartan 3 FPGA module. Please see here for more details:- http://s100...VA-10%20Board.htm We have also completed a prototype 80286 S-100 master/slave S-100 CPU board. In my system this runs with a clock speed of 12MHz. It is the next stepping stone from our earlier 8088 and 8086 CPU boards. It works with the 20 or so other S-100 boards we have done and allows one to boot CPM86 or MSDO... [ read more ]

Lee Felsenstein Visits MARCH / Workshop

by billdeg - 07/05/2012
Total messages in this thread: 1
Lee Felsenstein 2012 MARCH Workshop
Pioneering microcomputer advocate and engineer Lee Felsenstein paid us a visit at our most recent MARCH club event June 30 / July 1st 2012. That's me in the middle. Click image for larger view.
Members of the Mid Atlantic Retro Computing Hobbyists club value these hardware restoration workshops because we can share skills and experience. We gather from all points north and south to set up ad-hoc workshop tables with our favorite tools and parts bins. Each of us bring a vintage computer or two and we work to clean and restore the systems to full functionality. We often go to the wee hours, but the time goes by fast. [ read more ]
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