Dear Bill,

     About 15 years ago, I was brazen enough to replace the bearings on an
older Balzers (now Pfeiffer) turbomolecular pump. Two of my colleagues
heard of this and still call me the  "Kid".  Some of
the students just call me "Brazen." I have repented of such foolishness!
     There are several problems: 1) the instructions in the manual were
incomplete, and I think they
still are, 2) you need some expensive tools from Pfeiffer (the pulley
puller can be purchased locally
from an auto parts store), 3) you need some training, and 4) you need a
spin balancer to get the turbine in balance (without this latter tool, your
chances of successfully doing the repair, and NOT DESTROYING the turbo are
less than 30 % (my best guess).

Good luck,  Buena suerte, Viel Gluck,

Glen





                    Bill Winston
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                    Sent by: Stable       Subject:     turbopump bearings
                    Isotope
                    Geochemistry
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                    07/08/02 03:27
                    PM
                    Please respond
                    to Stable
                    Isotope
                    Geochemistry






Greetings,

I am in need of some advice regarding a Pfeiffer TMH 064 turbopump
problem on our Finnigan Mat 252.  We are getting a "Rotor Jammed" error
from the turbopump controller and I am considering sending the pump back
to Pfeiffer for service.  We have two controllers and two pumps and I
switched controllers between them and determined that the problem lies
with the pump and not the controller.  I have removed the pump from the
instrument and am able to turn the rotor by hand but it does not rotate
very freely.  The cost for a bearing replacement is $700 (with ~4 weeks
turn around!) but I could get the bearing assembly for $250.  The pump
manual mentions "special tools" and "necessary training" required to
carry out the procedure but does not give details.  Could anyone share
any similar experiences with this model turbopump or describe the
necessary tools and replacement procedure?  I would also be very
interested in finding a cheaper supplier for the bearing assembly, if
possible.

Thanks for your help!

Bill Winston
Stable Isotope Research Specialist
Washington University
Earth and Planetary Sciences
[log in to unmask]
Lab: 314-935-7475
Fax: 314-935-7361