The 80 Hz peak was not present in any of the spectra I looked at before the last lock on the 31^st of Oct. UTC. Starting with the next lock on Nov. 2, it was always present in spectra that I looked at.  Possible sources of changes in the alog include PMC and ILC modifications, PSL polarizer work, problems associated with CO2Y, changes in PMC locking electronics, and, of course, alignment changes. I did a quick re-check for new scattering sites from alignment changes, but found nothing.