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Projects for the Heath-Zenith
Z-100 8080/8088 Dual-CPU Computer

Gemini Board PC Emulator for the Z-100

Gemini Board: Photo courtesy of Steven Vagts of Z-100 LifeLine The Gemini Board was a PC emulator circuit board designed to plug into the Z-100 motherboard and provide better IBM-PC compatibility mainly at the BIOS level.  The board had a separate 8088 processor dedicated to handling BIOS and video compatibility.

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Z-100 Fan Replacement

All of this noise from such a little fan. The stock fan inside of the Z-100 power supply is a 12 volt Panasonic Panaflo FBP-08B12H with an airflow rating of 32.9 CFM (Cubic Feet per Minute). The acoustical noise rating is a stunning 39 dbA! While the stock fan moves a

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The Definitive Z-100 Software Archive

After months of 19.2K and 38.4k serial data transfers, I now present to you a Z-100 software and manual archive like no other on the Internet.  The bulk of my Z-100 manuals have been scanned and OCR’d and all 232 5 1/4″ and 8″ disks have been digitally archived for

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High Speed Imp v2.46

With my collection of CP/M systems growing, I decided to make my high speed version of IMP platform independent.  I’ve removed the hardware-specific code from the main program but kept the code changes to support baud rate tables up to 115k.  This means you can apply any existing IMP overlay now as

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Z80Pack CP/M Emulator and NZ-COM

Z80Pack by Udo Munk is a great CP/M emulator.  It will emulate a number of hardware architectures including the Altair and IMSAI systems, but I primarily use it CP/M development environment.  I can quickly write or edit CP/M programs and on my MacBook and then transfer them over to my Kaypro or

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Repairing an 8″ Floppy Drive

When I first powered up the Z-100 for testing, everything worked except one of the 8″ disk drives, a Tandon TM848-1E.  The drive light would make three short flashes, then one long flash and was not detected by the OS (neither CP/M nor MS-DOS).  The Tandon manual didn’t list this particular blink

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