|Winding:||Automatic, Bi-Directional Automatic Winding, Central Rotor Automatic Winding|
|Diameter:||28.0 mm (12.5 ligne)|
|© ETA||Complications:||Hacking Seconds|
|Hands:||Central Hour Hand, Central Minute Hand, Central Seconds Hand|
|Distinguishing Technical Characteristics|
Clockwise Balance Cock
|Production: 1983 –|
ETA’s 2890 was an ultra-thin automatic watch movement and the first in the ETA 2890 family. It was introduced in 1975, as Eterna’s movement operations were folded into ETA, and removed from production in 1983. The ETA 2892-2 (with date) was the successor movement.
Closely related to the short-lived Eterna 1504, the ETA 2890 operates at 28,800 A/h, has 21 jewels, and features an automatic winding system embedded into the movement rather than attached above it. This gives it the signature 3.6 mm depth which remains the hallmark of the family to date.
The ETA 2890 and closely-related ETA 2892 (with date) measured 12.5”’ (28.0 mm) in diameter. The oscillating weight extended to the edge of this plate, effectively winding the stiff mainspring needed to drive the high-beat 28,800 A/h balance.
ETA 2890 Family Overview
The ETA 2890 family is a series of slim and robust automatic watch movements produced by ETA since 1975. They are generally regarded as superior to the similar ETA 2800 family. Cal. 2890 and its successors is based on an Eterna design, with ball bearings on the rotor and a smaller balance wheel in the modern style. The family remains one of the leading watch movements to this day.
The most well-known movement in this series today is Cal. 2892A2, a highly evolved automatic movement with central seconds and a date wheel. Because of its slim dimensions, Cal. 2892A2 is often paired with modules to add world time, power reserve indicator, chronograph, and other complications.
Distinguishing features of the ETA 2890 family include a smaller balance wheel than historic movements, including the ETA 2824 family, and a large rotor hub located with seven visible bearings. The balance is located at 12:00 when viewed from the back with the crown at 9:00, and is located by a clockwise cock with an eccentric screw for regulation.Images are taken from official publications and are used here for commentary and educational purposes. Copyright is held by the original owner as noted.