This system appears to have originally been a 16KB diskless model, which was upgraded to 48KB, 2 drives and the optional RS-232 interface. The drive upgrade was the Disk III system from VR Data, also the RS-232 board.

I picked up another Model III with a Holmes Engineering VID-80 board installed, and transplanted it into this machine. The VID-80 provides memory mapping to move the Model III ROMS out of low memory, to allow CP/M to run. It also provides an 80x24 display mode, and has an additional 64KB of RAM on board. This VID-80 has another Holmes upgrade, a Sprinter III. It has a Z80B CPU and is capable of operation at 5.07MHz.

I was able to verify that the 80x24 mode works, as well as the Sprinter III switching between high and normal speeds. The machine boots up by default in 80x24 mode, but holding the '6' key while booting brings up 64x16 mode. I am unable to test CP/M because I don't have the Holmes CP/M software. If anyone has a copy of Holmes CP/M for the VID-80 or any documentation, please let me know.

Update (09/29/2025): I was able to find someone with a Holmes CP/M disk and arranged to have it brought to VCF East in April. We attempted to image the disk with a Greaseweazle but due to operator inexperience were only able to get a partial copy. I was able to create a bootable system disk with what was recovered, although a bunch of programs were missing. The Holmes CP/M format is available in Montezuma Micro CP/M, so I was able to read, write and copy the image files on the SDLTRS emulator.

Holmes CP/M works well on the Model III VID-80. I wrote a pair of short ASM utilities to switch the Sprinter III into Fast and Normal speeds (I did the same for LDOS, DOSPlus and NewDOS/80). Wordstar installed without a problem. The 80x24 font is a little hard to read, but is definitely usable. I exhibited the Model III at Tandy Assembly in Springfield, OH, and it ran all weekend without a problem. I also upgraded the system with a Gotek as drive :0 and a FreHD, for use with operating systems that support it.