Omega Seamaster Omegamatic - Omegamatic Caliber

Omegamatic Caliber

Omegamatic used Omega caliber 1400 (ETA 205.111 Rhodium plated), 17 jewel autoquartz (not thermocompensated) movement with around 100 hours power reserve. This caliber has the option of manual winding to get the initial power to the capacitor. The mechanism alerts low power reserve by moving the seconds hand in four seconds intervals. The Omega 1400 caliber has a slow date change, which usually takes approximately 1.5 hours to change over.

Production of ETA 205.111 started in 1996. It was superseded by ETA 205.911, which replaced the capacitor with a rechargeable battery. Technical documents of 205.111 caliber could be retrieved from ETA customer service portal

The capacitor used in Omegamatic watches is a Renata GC920 (9.5 x 1.9 mm 2.4V 0.33F). in the event of failure due to electrolyte leak, this capacitor could be replaced by a Panasonic MT920 1.5V (ETA MT920/Citizen 298-177) rechargeable battery. Another compatible rechargeable battery is the Maxell TC920S lithium-ion cell (Seiko 3023 xxZ).

For other failures, the best option would be getting a watch with a 205.911 caliber (Tissot PR100 autoquartz) and use it for spares. The use of a Swatch autoquartz it is not recommended as these carry the inferior ETA 205.711 15 jewel caliber.

ETA 205.111 technical communication document, in electrical test section, states that capacitor voltages will fluctuate from 0 to 2.4V. It also documents that external power supply tests are to be run with 1.55V (measured with the capacitor in place).In ETA 205.911 technical communication document, Interchangeability (List of material) section, it is listed that the major parts that differ from 205.111 caliber are Generator (part no. 20.590.00 for 205.911 and part no. 20.515.00 for 205.111) and accumulator (part no. 20.575.00 for 205.911 and part no. 20.802.00 for 205.111 - capacitor). Demo-version of the ETA ONLINE SHOP list the generator for caliber 205.911 (Article no, 04203.205111 (CS) / 251987) as part no. 20.515.00 (the same part number for caliber 205.111) and it specifically mentions that it is compatible with calibers 1400 B, 205.911 C and 205.911 E.

Omega caliber 1400 is compatible with Panasonic MT920 (nominal voltage of 1.5V). Even though MT920 is designed to last 500 charge-discharge cycles, due to lack of official documentation, it is not clear how long this titanium lithium rechargeable battery will last when used in Omega 1400 caliber.