Roughly 10000 of these Sol-20 or Sol Terminal Computers were manufactured in either kit or pre-assembled form from 1977-1979. The company that made them was called Processor Technology Corporation in Emeryville California and was founded by Lee Felsenstein, Gordon French and Bob Marsh around mid 1975. Of course Lee Felsenstein later worked on the Osbourne portable computer as well. The Sol-20 has an important place in the history of computer for a number of reasons. It was one of the first personal computers and one of the first with a built in keyboard. It also had a built in video driver or VDM-1 card (video display module) which allowed connection to a composite monitor or tv set (with some modifications). The integration of the components inspired Steve Jobs to do the same with the Apple 2 which came out roughly a year later.
The Sol-20 used the Intel 8080 processor and ran at 2 MHz and had 5 S-100 board slots. In fact Processor Technolgy Corp designed a number of S-100 boards for video, memory and Tape input output. The S-100 boards were one of the first standardized components in early personal computing originally designed by Altair and used in a number of computers in the mid to late 70’s. The Sol-20 could accommodate from 8k to 64k RAM.
Processor Technology Corporation originally planned to offer the SolPC, the Sol-10 and the Sol-20. The PC being just a motherboard and the Sol-10 a stripped down Sol-20. It’s not certain whether any Sol-10’s or Sol PC’s were ever actually shipped though. The motherboard alone was priced at $745.00 pre-assembled. The Sol 10 was supposed to retail for $1295.00 and the Sol-20 for $1495.00. You could also buy the Sol-20 in kit form for $1095.00. If you were looking for a full system Processor Technology Corporation offered one for $5450.00 which included the Sol-20 with SOLOS operating system, a Helios II 8″ dual disk drive, 2 16KRA memory boards, a PT-872 TV Monitor and Disk Basic diskette. The Helios II floppy disk system alone was nearly $2700.00.
The Sol-20 had very distinct styling with the blue case and walnut wood side panels. It was essentially personal computer that you could buy pre-assembled that didn’t look like a square box (such as MITS Altair 8800 or IMSAI 8080). It was also used fairly extensively for business applications where before only expensive mainframe style computers were used.
The Sol-20 is a fairly difficult computer to find though they do come up for sale once in a while. The last sale in March of 2012 resulted in a $832.00 sale price. It was sold as-is but allegedly working though it only seemed to have one S-100 board.
Probably one of the best Sol-20 resource sites on the web is Sol20.org.