15 m Li-COR (sn1176) dropped out of service on November 6, 2011.
Note, by Gordon, Jul 13, 2012: There is no sn1176. I think this must have been unit sn1167, which according to the log entry of 4/12/2011, was installed at 15m.
The diagnostic value dropped to 215 indicating that Bit 5 signaled that the instrument's chopper motor failed. There was an indication a number of hours earlier that the chopper motor was beginning to fail, see:
http://www.eol.ucar.edu/isf/projects/BEACHON_SRM/isfs/qcdata/plots/2011/11/06/licor_20111106.png
Chris and I made a trip to MFO to move the 7m Li-COR (sn 0813) up to 15m and to remove the dead instrument from 15m. The tower is therefore operating again with three levels of water vapor and CO2 fluxes (2m, 16m, 43m). See Chris' entry for details of this instrument swap and timing.