In 1984, I purchased a used Terak from the Michigan State University Computer Laboratory, where I worked. This was the very same unit I had used years before. But developments in the microcomputing industry had long overtaken it, and the machine had been unused for years. I bought the complete system for $260; it had cost the Univesity $12,000.
The 8510A system unit has part number 90-0000-001, serial number 9020776. There's a second floppy drive, known as model 8512. The monitor has a December 1978 date of manufacture.