"This rare scientific desktop calculator looks and feels like a TI-30 LCD. It uses indeed an identical electronic to the well known TI-30 family. Texas Instruments wasn't very successful with their desktop scientific calculator line"

For me it is the most succesfull calculator ever. As a young engineer the company gave me one mid 1984, and 3 other collegues bought one. It is a unique machine: scientific, geometrics on a desktop machine: no small buttons, no small display, not a second hand needed to keep the calculator on its place while working.

New collegues in 1986 and 1987 wanted to have the same calculator but unfortunately these were no longer available in the Netherlands. They tried until 1992 to buy one, from eastern Germany to south Africa. After a 5 year desparate search they seemed to realize they would never possess one.

My machine refused his correct work last year in 2012: The rubber layer under the buttons was torn under the much used buttons. Now it was my turn to be desparate. Tried to get in contact with a retired collegue who took the calculator home 9 years ago when he retired. He told me this his machine did not work correct anymore (some buttons refused) and gave it to me. I opened the machine and the same had happened: Rubber inlay torn under much used buttons. I tried to make one good rubber screen out of two torn pieces. I replaced the untorn parts (not much used buttons) with my torn parts. The repairwork was succesful, and, unbelievable, the calculator resumed his work.
So almost 29 years my TI30D is my best office friend ever. I hope and pray it will keep working until I retire in 11 years.