The device is programmable from the calculator that is attached to the board, or optionally there are pads on the circuit board for connecting a serial port. This is a rare collectible due to its unusual combination of computer development kit and calculator user interface.The device powers up and says "CPU Ready", which is what is supposed to do. I have also verified that the keypad works and that you can enter a string.
I have not done any additional testing, so please keep that in mind. The item "Vintage Texas Instruments TM 990/189 Microcomputer, Used, working" is in sale since Saturday, August 18, 2018.This item is in the category "Computers/Tablets & Networking\Vintage Computing\Vintage Manuals & Merchandise". The seller is "kcounsel" and is located in Huntsville, Alabama. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Israel, Mexico, New Zealand, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Dominican republic, Panama, Trinidad and tobago, Guatemala, El salvador, Honduras, Jamaica.