24e7d3a5_FAQs___3M_ESPE_Suomi__Possible_Cause
[Problem] The power level display of the handpiece flashes red. The ongoing exposure is interrupted (light off signal is emitted) followed by a 2-second error signal; the and piece switches to 'sleep' mode and resists further activation. [Solution] Place the handpiece in the charger and recharge the battery. [Possible Cause] 
The battery lacks sufficient charge.
FAQs - 3M ESPE Suomi
Possible Cause