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Bunch of little things

by billdeg
Total messages in this thread: 1
1) I built from parts two more IBM systems, one IBM stock dual drive 5150 PC and an IBM XT 5160. The XT has a ST 412 HD, with AST Six Pak. - 640K RAM and 10MB - who could need more than that? I put IBM DOS 3.3 on the HD. 2) I got my Northstar Horizon to boot using the ADM 3A terminal. 3) I have been able to successfully type in a lot of programs into my IMSAI lately (using CUTTER monitor program), and the system holds long enough to complete and run the program. 4) EC-1 - New oscilloscope and pictures of underside wiring">... [ read more ]

Reforming Electrolytic Capacitors

by billdeg
Total messages in this thread: 1
Originally posted on Midatlantic Retro Yahoo Group: - In, Mike Loewen wrote: > > > I tore apart my IMSAI in order to remove the four large electrolytic > capacitors for testing/reforming. There are two 9500uf-30VDC caps and two > 95000uf-15VDC caps. Here's the rig I put together for bringing them back > to life: > > http://sturgeon.css.psu....I/Reforming-L.jpg > > I put this together after reading many documents about testing old > capacitors. Hidden behind the cap is an 8K power resistor in series with > the cap. The small meter is measuring the voltage output from the the > power supply (a HP 6443B 0-120VDC/2.5A unit), in this case 25.0 volts. > The large meter is measuring the current flowing through the cap, 0.11ma. > The voltage across the cap is 24.7V at this point. > > I started">... [ read more ]

IBM PC 5150 Dump a BIOS using

by billdeg
Total messages in this thread: 3
Updated: [ Another 5150 A BIOS DUMP ] 04/04/2009
This is a mirror of the original page C:> DEBUG -N MYF000.BIN (resulting file will be named MYF000.BIN) -R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K) BX 0000 :0000 -R CX CX 0000 :8000 -M F000:0 8000 0100 (copy 32K bytes from F000:0 to offset 0100 in local segment) -W 0100 (write from offset 0100 in local segment) Writing 8000 bytes -N MYF800.BIN (resulting file will be named MYF800.BIN) -M F800:0 8000 0100 (copy 32K bytes from F800:0 to offset 0100 in local segment) -W 0100 (write from offset 0100 in local segment) Writing 8000 bytes -Q C:>copy /b myf000.bin+myf800.bin final.bin (optional, concatenates together the two myfxxx.bin files into final.bin)">... [ read more ]

Another IBM 5150 16KB-64KB CPU

by billdeg
Total messages in this thread: 1
I traded a working IBM 5150 with 64KB-256KB CPU for an earlier (but not working) 16KB-64KB CPU Model.
This is a 10/1981 model, without the IBM-labeled disk drives. I have not yet confirmed that IBM sold systems with non-labeled drives, or whether these were added by the reseller to save money. The date stamp on the IC's of the drives range from 1980-2nd week of 1982, and one could theorize that the drives were added later, after market. That explains why they're not "IBM" labeled. Just my hunch.
I swapped out a working 16KB-64KB CPU board and brought the system back to life. The drives work, I did not test the CGA card that also came with it. The previous owner had both a monochrome and CGA card installed, which may have caused the motherboard to short out. Not sure. A">... [ read more ]


by billdeg
Total messages in this thread: 1
My personal favorite 8088 GRiD laptop is the Model 1040 GRIDLITE PLUS.
The GRiD 1040 had a blue on blue LCD display. This specimen has both the internal 3 1/2" 720 disk drive and an external model 3402 5 1/4" drive.
This laptop came out in 1988, but I recall seeing this model in service as late as 1993. Unfortunately the power supply was poorly designed. Many still-functional system exist if you can find a working power supply for it.
The GRiD external 5 1/4" disk drive required it's own separate power supply.
DOS is stored on a ROM, and the version is 3.21. The ROM drive is "A", the internal 3.5" disk drive is "C", and the external 5 1/4" dr">... [ read more ]

New blog on (some) rare and old computer

by cyberfritz
Total messages in this thread: 3
Updated: [ Spreadsheet version: yes ] 03/31/2009
Dear all, if you like this blog, you might want to consider also this (I admit it, my) blog: A major contribution (at least that's what I hope) of it is my Ebay prices list of some rare computers together. The blog is all about some rare computers, about the rarity of old computers, and mostly theoretical thoughts about collecting rare computers. In contrast to this excellent blog, you won't find technical how-tos or technical tips and tricks. I'm looking forward your visit. Regards, cyberfritz">... [ read more ]

The Bouncing Beastie

by billdeg
Total messages in this thread: 1
The Bouncing Beastie by Martin Winzenread appeared in the September 1976 Dr. Dobbs Journal: http://vinta...Demo%20Program.pdf I typed in a version that will work on the Processor Technologies' CUTER program with the VDM-1">... [ read more ]


by billdeg
Total messages in this thread: 1
Evan gave me a GRiD GRiDPAD 1910 laptop without a power supply. Using another GRiD powersupply that feeds 17.25V I was able to boot this system.
The GRiD GRiDPAD 1910 touch-screen laptop.
The touchpad has some bad spots, but I was able to look around. There are three drives, all stored in ROMS, no disk drives. Pictures of GRiD laptops">... [ read more ]

Hacking Weekend

by billdeg
Total messages in this thread: 1
This weekend a few friends from the MidAtlantic Retro Computing Hobbyists came by to work on old systems. Here are a few pictures.
Moving a wheel barrel full of TRS 80 Model II's Click image for larger picture.
Dan Ragonti was able to almost get his PET 2001-8 working by swapping parts from a working PET for comparison purposes, and replacing RAM. PET 2001-8 pic 1 PET 2001-8 pic 2 PET 2001-8 pic 3 ">... [ read more ]

Xerox x973 Dual 8

by billdeg
Total messages in this thread: 1
Quiz: what drives are in this Xerox x973 Dual 8" drive?
Xerox x973 Dual 8" drive
A) Shugart 801 B) Mitsubishi M2896 C) Tandon 848-2 Answer: A">... [ read more ]

Micro World Sept. 1976

by billdeg
Total messages in this thread: 1
"A Computer Newsletter for the East Coast" (USA)
Click image for PDF to download. This is a home-brew 'zine (note spelling "intorductory") example probably included in the goody bags of registrants to the Personal Computing 76 Consumer Trade Fair in Atlantic City, NJ. The event was August 28 and 29, 1976.
">... [ read more ]

Heathkit EC-1 Analog Computer

by billdeg
Total messages in this thread: 1
This is the oldest complete computer in my inventory.
The 1960 Heathkit EC-1 is one of the first desktop computers. This is an analog computer with no RAM and whose display is an oscilloscope.

I will post more information about this system once I finish reading the manuals and testing the connections, etc. In the mean time, here are some pictures.">... [ read more ]

ROM Computer Applications for Living

by billdeg
Total messages in this thread: 1

ROM Computer Applications for Living was a short-lived magazine in the later 70's. This issue has an interesting article by Ted Nelson about the development of computer screen technology titled The Art of the Computer Screen. Nothing says "hi-tech" like needlepoint, right?
">... [ read more ]


by billdeg
Total messages in this thread: 1
Artist's rendering of the XEROX Dynabook notebook computer.
From the People's Computer Company May 1976 newsletter: "..We've been hearing about the Dynabook fantasy for a long time. Below are some excerpts from the recently published report on the Dynabook project, entitled "Personal Dynamic Media" by the Learnmg Research Group, Xerox Palo Alto Research Center. .." Click to download PDF of this article">... [ read more ] references

by billdeg
Total messages in this thread: 1
10 steps in the evolution of portable computing Note some of the pictured systems were supplied by, as well as frieds Evan Koblentz (Pres MARCH) and Erik Klein (">... [ read more ]
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