I have been trying to reconcile the difference in laser room temperatures as measured by a temperature
sensor on the PSL table and the PSL environmental temperature sensor.  Back tracking through the
schematics ... etc. the signal H1:PSL-FSS_DINCO_REFCAV_AMBTEMP_OUTPUT corresponds to approximately
-2.207 V.  That would imply that the ambient temperature is over 40 degC, which clearly it is not.
An infrared camera image suggests the ambient temperature is around 22 degC with a couple of people
inside the enclosure.

    What may account for the discrepancy?
 - broken AD590 temperature sensor
 - non-zero voltage coming out of the DAC card, which is the ambient temperature reference signal
 - broken LT1021-7 in the temperature box
 - something else I cannot account for (always a distinct possibility)

Will try and sort this out in the next few weeks.