PeterK and RickS
We intended to make weekly PSL performance assessment measurements this morning, but we found that the FSS had not locked since about 4 PM yesterday afternoon.

After 6 hours of so of investigating, we found that there was a mouse in the RF distribution rack (one that likes Swiss chocolate!).

It seems that the 80 MHz RF distribution is being reconfigured.  After restoring the RF drive to the VCO and FSS AOM, the FSS locked right up, the ISS locked, and the system appears on cursory inspection to be operating as expected.