[1][2] For its era, the 3900 is extremely advanced; it has a 4-inch (100 mm) cathode ray tube screen to produce a 5-line display, has separate memory for storing three intermediate results, supports numerical rounding, and is still "smaller than a typewriter".

GMe had problems producing the PMOS ICs in quantity, ultimately requiring half of the 29 chips to be redesigned to wider tolerances.

Victor Comptometer of Chicago had a successful line of mechanical calculators but concluded in the early 1960s that they were destined to be replaced by electronic versions.

To gain familiarity with the basic concepts, in 1962 the company put together a team to build a prototype using vacuum tubes.

In 1964, Howard Bogert built a simple 8-digit calculator using GMe's Milliwatt Logic ICs, and a small article on it was published in Electronic News in March 1964.

Friden, Inc. had recently introduced a system using a small cathode ray tube (CRT) display.

Bob Norman purchased a Sony portable television, pulled out the tube, and began adapting it to the calculator role.

[4] The prototype was running in early 1965 and attention turned to producing the ICs that would replace the printed circuit boards (PCBs) containing dozens of Milliwatt chips.

The conversion was carried out by converting one PCBs at a time until 23 new ICs were completed and the prototype was up and running in all-IC form.

The system was formally announced at the Business Equipment Manufacturers Association in October 1965, with deliveries expected in early 1966.

In early 1968, Ford managers visited the GMe offices and decided it should be moved to Philco headquarters in Pennsylvania.

Philco eventually decided to simply close GMe and the product was abandoned[4] in June 1968.

Numbers are stored in a 22-digit binary coded decimal (BCD) format and displayed on up to five 20-digit rows on the screen.