If the slave laser has come unlocked, and the clearest indication of
this will be an inability to lock either wca combined with very low
LASER SYNTHESIZER PIEZO-VOLTAGE and PLL-IF-LEVEL (see below), these
are the steps to reacquire lock.  (as of 17 Jun 2008 - from Jason
Castro in Charlottesville)

1) On the Labview GUI called "Central LO Rack Monitoring and Control",
   find the "Subarray 2" area, and check that the value for the Reference
   Freq is correct (e.g. 85.5 GHz) and that the CVR frequency is equal to
   (Ref-0.175GHz)/5.  You can check the CVR frequency from objExplorer.

2) Click the "Details" button under the "Slave Laser Error" box.  This
   will bring up a new window called "Laser Synthsizer/Slave Laser M&C".

3) In the middle of the lefthand side window, unclick the "Read Frequency
   from Laser" control button.

4. Set the beat frequency to the Reference Freq from the previous GUI
   (e.g. 85.5 GHz) by typing the value into the box, and then clicking the
   button "Set Beat Freq".

5. If the LED called "ERROR Frequency NOT reached" is illuminated, then
   press "Calibrate CTNLL".

6. Press "Set beat freq" again.  You should notice the PLL_IF_Level jump
   up and the PLL_VCO_Tune spike upward and (probably) decay again.

7. Click "Auto correction" to be enabled, and press "Set beat freq" again.
   The "correction active" LED will illuminate and probably go out again.
   Press "Set beat freq" again as soon as it goes out.  Try this a few
   times.  The target CNTL_V is 2.5V, and the PLL_IF_Level should be above
   3.5V (e.g. 4.38 V).  The piezo voltage can be read from the
   objExplorer, under OPLL -> CONTROL/AOSTiming/OPLL -> PIEZO_VOLTAGE. It
   should be a healthy value, ~12 V. If its 0.44V, then the laser is
   probably not locked.

8. Once it is locked, leave "Auto correction" enabled.  If it does not
   lock then try use the lower buttons on the GUI to step or up or down by
   3MHz.  If this doesn't work, try using the upping buttons to step the
   beat frequency up or down by 0.1GHz.  Alternatively, use Gene's psi
   script ("c sl rlk"), which we believe performs this kind of search
   automatically.