Ethan -- They are exceedingly rare boards. It took me almost three years of waiting before I was able to find one for my Gazelle. I really haven't been able to find a 1-for-1 substitute. The CompuPro System Support Board comes close, but would require a lot of customization to work. Rich -- Rich Cini http://www.classiccmp.org/cini http://www.classiccmp.org/altair32 On 6/13/18, 6:04 PM, "vcf-midatlantic on behalf of Ethan O'Toole via vcf-midatlantic" <vcf-midatlantic-bounces@lists.vintagecomputerfederation.org on behalf of vcf-midatlantic@lists.vintagecomputerfederation.org> wrote: Howdy! I picked up a SCP 200B 8086 CPU board, and there is a companion board called the 300 board that contains bootstrap code, a serial port and a few other functions. By any chance does anyone know where I might find one? - Ethan