[ChazzyD]

Open the little sucker up and turn the little dashpot on the circuit board 'til it starts working and then fine tune by turning ever so little bit of a turn 'til you get the best range out of it. Screw it back together.
Charles

 

[ChazzyD]

Of course, use a fresh battery and don't be surprised if it requires lots of patience and a bit of time to get it to even start working.
Charles