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Hi all, Just wanted to share what I've been working on lately. This is a 16 bit ISA expansion card that provides 8MB of system RAM and 8MB of EMS RAM. It uses 30-pin SIMMs, because I have always used SRAM for projects and wanted to play around with DRAM for once. Boards have been ordered and...

Hi all. One of the projects I have been working on lately is recreating the PCB for the IBM EGA memory expansion board (part number 6480099). I'm going to have board made either way to expand my own system, but I was wondering if there was a need out there and I should get extras? They seem to...

Hi all. I ended up with one of these cards but the system doesn't boot with it installed. I'm not seeing anything physically wrong with it but the BIOS EPROM is missing the cover over the window, so I'm wondering if it might have been partially erased over the years. Does anyone happen to have...

Inspired by the Lo-Tech 1MB RAM board which is great for adding UMBs to XT class systems, I set out to design a 16 bit version for AT class systems. It can selectively fill 0-512K in 64KB chunks (which is probably already maxed out on most ATs) and 512-1024K in 32K chunks, though obviously some...

I recently acquired a IBM 5170 machine and would like to get a 5154 monitor to match. Will pay a fair price plus shipping, or I have some items I could trade including an Apple IIGS or SGI Indigo system. Maybe something else, let me know what you're looking for.

Hi all, I'm finally to the point of adding RTC support to the "CheapBus" system I've been working on (see here if interested). Looking at the way CP/M expects the date to be formatted, I wonder if it is going to handle the year correctly? Has anyone implemented this and what do I need to look...

Does anyone have a good copy of the schematic for the Tarbell cassette interface? I'm trying to recapture it in KiCad so I can make a PCB for a quasi-replica. I have found a couple PDF copies of the manual online, but they are scanned at fairly low resolution making it hard to make out some...

I'd like to give an IMSAI 8080 system a good home. Working or not. Looking to spend US$2000 or less. Thanks.

I am working on building an MPU-401 clone device. It would be good to have "the real thing" to test against, so I'm looking for an MPU-401 (with or without interface card) or MPU-IPC(-T) (with out without breakout box). Please let me know if you have or know of one for sale for a reasonable...

Hi all, Since it seems to be almost impossible to find a real MPU-401 or compatible, I am going to attempt to create my own. Once the design is complete, the hardware and software will be open source so others can build them. I am also going to try to offer boards and/or kits for sale (but NOT...

I have this Model M keyboard, P/N 1392595 that I acquired with a 3127 terminal. It has an RJ45 connector on it. I plan to"convert it for PC use, but before I do that I figured I should check if anyone wants to swap for one that is already set up to plug in to a PC. I'd even include the terminal...

I bought this system a long time ago at a thrift store, but I just never use it. It includes the main system, color monitor, memory upgrade board (for a total of 640K RAM), external 3.5" floppy drive, and a DOS 6.22 boot floppy. Everything works good with the exception of sometimes the internal...