At 14:25:00 and 14:26:00 a signal was injected into the seismometer channels for H1:PEM-MX to test a suspected delay in signals showing up in dataviewer displays in the control room. There was no delay. Signal was injected by striking the floor of the VEA with a heavy plastic mallet. There is a time conversion issue on playback in dataviewer in which the UTC time entered is not the time that gets played back, but if GPS time is used, it is correct. This will be investigated and corrected.