While an EMS is nice, it isn't necessary and may possibly be damaged by whatever problem you currently have. I would
1 Disconnect the power cord from the pedestal and check the voltage. If somewhere between 108 and 124 then
2 with the cord disconnected, find the main panel and check all the connections to the breakers and ground.
3 If all ok turn off all the breakers and reconnect to the pedestal (note* You should always make sure the breaker at the pedestal is off when connecting or diconnecting.)
4 At this point you can turn on the breakers one at a time to determine which one is causing your problem.