Make sure that you let the 627 warm up for 4 hours. The zero will drift during the warm up but will be rock steady thereafter. I have a 1 Torr 122B which is not temp regulated so I have to check the zero from time to time. (But, the drift is sub-1 micron in my basement lab ambient, much lower than my typical operating points.)
If the cold cathode is demountable (it really should be), don't ever try to clean it with anything magnetic. 3M Scotchbrite is good but make sure you wash off the plastic grit residue.
Your pump should emit an audible whine but if it's really screamin' or the sound varies a lot, you may be in need of a bearing lube (but hopefully not a bearing replacement). Alcatel sells lube kits for somewhere around $50.
Two nice things about the drag pumps are the modest forepressure requirement (10-20 Torr) and the relatively slow rotation of the pump (30k rpm range) which makes them less susceptable to mishandling-related damage. The only downside is the lesser ultimate vacuum but in a reasonably clean system you can easily get to the -6 range.
Steve
Created on Friday, April 13, 2001 8:45 AM EDT by Steve Hansen