P.E. 9600 thermocyclers-the cooling fix...

Christopher G. Alpha cga3 at cornell.edu
Mon Feb 3 12:53:25 EST 1997

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?)   ;)

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