Comment drytek2 SNF 2008-07-07 15:51:03: Pot ordered ....

[shott at snf.stanford.edu]

I've ordered the appropriate Bourns 10-turn wirewound 20 kohm linear 2W pot (Bourns part number 3540S-1-203).  I will need to make sure that I know how to apppropriately shutdown the system in order to pull out the appropriate sub-assembly and replace the part.  At this point, I believe that the system must be fully powered down and the pumps must be turned off in order to safely make this replacement.
John