The mic in the EY electronics bay had been reported by Vinny Roma as having unusually low signal, requiring a calibration factor 10 times larger than the other microphones.  I determined that the fault was with the signal conditioning box - when plugged in to a different channel, the microphone performed normally.  Additionally, I verified that the power supply was delivering the proper voltage to the signal conditioning box.  Using the second channel in the signal conditioning box also did not improve the signal.  We should plan to replace the signal conditioning box next week.