Citizen Caliber G900

The Citizen caliber G900 is a solar-powered perpetual calendar watch movement with a minute repeater function. This caliber is part of the G90* family of movements.

This movement was found in a Citizen Eco-Drive watch with “Calibre 9000” on the caseback.

G900 Solar Charging Times:

G900 top cover plate removed:

If you need to replace the capacitor (aka secondary battery) in your G900 powered timepiece, you will need to remove the top metal cover from the movement.

Below is what the main movement looks like without the cover installed:

G900 Capacitor Replacement:

Once the top cover is off, the capacitor is simply held in with a friction arm. Gently use your tool to remove the cell from the movement.

On the example watch shown, you can see that the original energy cell is a Li-ion CTL920 battery with Sony branding, made in Japan.  CTL920 or MT920 are the capacitor type, but you can’t use just any CTL920 or MT920 – you have to use the correct part number due to the tab position being oriented specifically for this movement.

The Citizen part number for the G900 replacement capacitor is 295-6900 aka 295-69. You can order it here.

Reset After New Capacitor:

Citzen makes it clear that they want G900 owners to send their watches back to the factory for capacitor replacement…

“Although the secondary battery is not required to be replaced as a general rule, there may rarely be times when the secondary battery does not charge properly. If a problem should happen to occur, promptly have the secondary battery replaced by an authorized service center.” -Source: Official G90X user manual (page 31)

However, unlike most other watch companies, they are also willing to provide information for what do in case you DIY – although it is sort of a game of page jumping in the manual:

“After the secondary battery has been replaced, perform the “All-Reset” and “Setting the Reference Position” procedures by referring to “4. Setting the Reference Position”. The watch may not operate properly unless these procedures are performed.” -Source: Official G90X user manual (page 33)

Video: G900 watch setting instructions

Additional Resources:

• Official Citizen instruction manual (pdf)

Note: This caliber listing is still being updated, but feel free to start discussions on it in the comments below…