Mark, What bothers me about your message is that you already have talked to Rigaku. Until now we have never been able to create a problem that they could not diagnose and help me solve from remote. In danger of offending ccp4 readers: specialized Rigaku experts are a remarkable source for information and solutions, probably better than we are.
Your most likely problem is that your nitrogen is not dry? Specifically, check your air dryer (sorry, nitrogen dryer) that it works appropriately. Very specifically, there reside two compressors inside the air dryer and if one no longer works, the quality of your nitrogen stream degrades. It may not be apparent if both compressors work, one can supply all the pressure and volume you need and is sufficiently noisy that you would not notice the second being silent. Of course this problem becomes obvious when you open up the cabinet. (Yes, of course this happened to us once before and in our case the compressor wiring was fickle, as in, working when the cabinet was open and not (always) working when the cabinet was closed; took FOREVER to find the problem.) Your second most likely reason is that the warm stream (outer stream) is not sufficiently protecting your cold stream from humidity, but this is not affected by your phi-axis position. We have two inverted phi-axes and we do not see icing, so there is no fundamental reason why the phi-axis should not be inverted. Mark ? -----Original Message----- From: Mark Agacan <m.aga...@dundee.ac.uk> To: CCP4BB@JISCMAIL.AC.UK Sent: Mon, 12 Jan 2009 3:42 am Subject: [ccp4bb] X-Stream 2000 problem - ICING Apologies for this slightly off topic question: I am having a great deal of trouble with my X-Stream 2000 cryostream system and I wondered if other users have similar problems. I've replaced almost all components (new GAST compressors, helium recharges, filters, etc., etc.) in the last couple of months but there is almost always icing of any cryo within 10 - 20 minutes of mounting a loop, and it is adversely affecting data collections. It appears like there is too much moisture in the cold or wam streams but the tubes have been fully dried out as per Rigaku advice. This X-Stream is attached to a generator with inverted phi axis and and i'm wondering if this could be the source of the problem, as the X-Stream for another generator in the same laboratory with normal phi axis does not ice up. Can some sort of turbulence around the loop caused by backdraft from the cryo hitting the inverted phi axis / camera mount cause excess humidity and lead to icing on the pin, loop and crystal? Has anyone else got this problem? Any suggestions would be very gratefully appreciated. Best Wishes, Mark _____________________________________ Dr Mark Agacan Scientific Officer, Division of Biological Chemistry and Drug Discovery, Wellcome Trust Biocentre, College of Life Sciences, Dow St., University of Dundee, Dundee, DD1 5EH Tel: +44 1382 388751 Fax: +44 1382 345764 _____________________________________ The University of Dundee is a registered Scottish charity, No: SC015096
