SEN0463 Geiger counter DoA?

Hi,

 

I purchased a SEN0463 Geiger counter, but it looks like it might be dead on arrival.

 

- Powered with 5V.- Power LED is on.- No beeps in either switch position.- No ACK LED activity.- No apparent activity on data pin as measured by oscilloscope.- Voltage across Geiger–Muller tube is a stable 214 V, which is somewhat less than expected. Touching my multimeter probe to the GM tube contact nearest the power/data header causes the beeper to beep and the ACK LED to illuminate.

 

Any ideas?

 

Thanks.