Brother EM-721

EM-721 is a model of Brother electronic typewriter. The keyboard appears to have been made by Brother, and uses their foil-in-dome capacitive system. This unit was assembled in March 1986 (serial prefix C6, C = March).

The PCB is part B48V032-3, with an apparent manufacture date of January or February 1986 (depending on how you read the dot indication). The most recent logic chip on the keyboard PCB is from January 1986. The only readable IC date on the display board seems to be December 1985. The small PCB with the Impact (L/M/H) and Keyboard (I/II/III) controls has PCB code B48V034-2.

The switches use a mixture of dome sheets and single domes, as with Topre and BTC practice.

Controls on either side of the keyboard allow it to be raised up, in a similar manner to standalone desktop keyboards.

Photos courtesy of Steve Kuterescz, E.T.ZONE.

Detail of the keyboard PCB:

The PCB date indication can only be assumed to read January 1986, with the active month shown by the most recent missing dot, read right-to-left, bottom-to-top as seems to be the prevalent scheme for Brother. No other reading would be consistent with the age of the machine.

Additional circuit boards for the typewriter: