EXFO FTB-1 - Manual (Page 193)

Maintenance
FTB-1 183
Cleaning the Touchscreen of Your FTB-1 Unit
Cleaning the Touchscreen of Your FTB-1 Unit
Clean the touchscreen with a soft, non-abrasive cloth, such as one used for
cleaning reading glasses, dampened with water.
Recharging the Main Battery
The main lithium-ion battery is offered in two sizes:

A four-cell (small) battery

An eight-cell (large) battery
The clock battery is recharged automatically along with the main battery.

In Mini Toolbox, the charge status is shown above Main Menu.

The unit also indicates the charge status with the LED on its front panel
(see LED Indicators Description on page 5):
C
AUTION
Using anything else than water can damage the special coating of
the touchscreen.
Status LED Battery Charge Status
Green Fully charged
Green, blinking Charging
Red Error or battery is not in the unit
C
AUTION
Only charge the battery with the AC adapter/charger (or the car
outlet adapter) provided by EXFO with your unit.