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Mark Ebdon mark at bioquest.demon.co.uk
Sun Feb 9 02:29:23 EST 1997

In article <5d58jo$pp0 at newsstand.cit.cornell.edu>, "Christopher G.
Alpha" <cga3 at cornell.edu> writes
>In article <528emb$3r0 at mserv1.dl.ac.uk>,
>   "J.P. Hays" <jph5 at leicester.ac.uk> wrote:
>>In reply to Clemens Suter-Crazzolara :-
>>We too have a Perkin Elmer 9600 PCR machine that is 3 - 4 years old and 
>we have problems with our machine (especially the cooling system). This 
>to be a fault with the machine (we don't trust our 9600 for PCR anymore). As 
>you mentioned the cost of servicing the machine is prohibitively expensive. 
>All I can suggest is for people to try other (more reliable) PCR machines!
>>John HAYS.
>>jph5 at le.ac.uk
>We've got the same machines too, running all day and night, and have 
>experienced chiller failure as well...BUT its just a question (generally) of a 
>little preventative maintainance every year or so.  So have at thee! If you 
>open up the machine, the cover tilts forward and locks into place, you will 
>see the fluid pump and reservoir (clear brownish plastic on ours).  Inside the 
>reservoir, the cap unscrews (be careful to note the positions of the parts and 
>the gaskets), there is a small cup-like filter for the coolant.  The coolant 
>BTW is basic auto antifreeze--20% E. glycol in dH2O, buy something good.  
>Often the problem when you have chiller failure and the diagnostics indicate 
>low flow as well--this filter is clogged.  It just gets gummed up with 
>deposits and bits of hose as they degrade over time.  If it looks 
>whiteish/opaque then take it to a sink and gently (its nylon and weak) scrub 
>it with a test tube brush until clean and water flows thru it ok.  Now flush 
>the system out with dH2O by attaching a tube to the line coming into the 
>reservoir cap and put the end of this to a beaker. (BE VERY CAREFUL here with 
>fluids and the electronics put something around the work areas to soak up any 
>spills from the reservoir etc...)  Fill the open reservoir with dH2O and 
>switch the machine on for a moment BUT DON'T LET THE FLUID LEVEL DROP BELOW 
>THE BOTTOM OF THE RESERVOIR, otherwise you will lose the prime on the pump and 
>get annoyed trying to prime it again (if you do: try backfilling the system), 
>and then switch it off, refill, repeat until clear water runs out.  Now flush 
>the dH2O out with your 20% coolant solution the same way until that runs the 
>right color.  Put all the pieces back in and gaskets seated properly, and 
>screw the cap on a LITTLE.  Leave it loose and turn it on, the level will drop 
>as air bubbles come out of the system.  Turn it off, open it up, top up the 
>reservoir, and repeat until you are sure its full and don't see any bubbles 
>(some bubbles may get trapped-so gently tap on things and they'll pop free).  
>Once satisfied tighten it all up and run the diagnostics again to verify that 
>either you fixed it or that you have a pump or condenser problem instead...
>USDA-ARS/Cornell University
>Plant Genetic Resources Unit
>Geneva, NY 14456
>anyone need a handy tech out there?  
>Or hey since it costs at least 800.00 US to have them look at one of 
>these, ship in to and from me and I'll do it for half, that's right!  
>HALF!!!  (just like some bad commercial, huh?)   ;)

Mark Ebdon

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