Ci6X instruments can appear not to power up. The display may flicker but remain dark when attempting to power up the instrument. This service bulletin describes the steps to install a new firmware version and correct this issue.
Remove the battery and disconnect both the USB cable and the power cord from the instrument
Press and hold the measure button while holding the shoe read switch closed (depress the instrument as though you are taking a reading) and connect the power cord. Release both once the display appears white:
Connect the USB cable
Start the Frimware Loader (this is the file downloaded from the link above)
Click the Get Version button
The monitor version should appear in the lower left corner
Click the Upgrade button
The status of the upgrade will actively update during the process. This process may take several minutes. DO NOT disconnect the USB cable during this process
"Success" will appear in the lower left corner when the process is complete.