Tandy 600

In checking through the master computer lists, I found a Tandy 600 computer that is not listed. In checking through the docs, I can't find any reference to what the CPU is and I would prefer not to take it apart to find out:). Anyone know what CPU it uses? The manual was copyright 1985 but I don't know when the machine was actually released although I would *assume* 1985. It operates with MS-DOS style files and with all software residing in ROM. It appears that the basic machine comes with 32K of RAM expandable to 128K or 224K with special 96K upgrade kits. It is classified as a "lap-size" or "handheld" computer; this with the dimensions being 11 1/2" x 12 1/2" x 2 1/2" and weighing about 9 1/2 pounds. It comes with a 16 line x 80 character LCD screen, 3 1/2" drive and a build-in modem. Built in software includes MS Works V1.2 with Word, Calendar, File, Telecom, and Multiplan.