A small quantity of electrostatic voltage sources were produced with defective circuit boards whose design could result in abnormally low voltages.
An acceptable circuit board has grooves cut into the board to decrease the change of conduction across the surface of the board:
A defective circuit board lacks these grooves:
To view the circuit board, remove the two Phillips screws in the back of the case and remove the back of the case.
After checking the circuit board, ensure the case is put back together and the screws put back in and tightened before operating the voltage source.