RE: Tube sticking on FACSCalibur

Paul,

In the past I have seen these intermittent tube sticking problems when:


.	  The lifter settings are too high or,

.	  The loader drawer is misaligned or,

.	  The tube seal is worn out


With a new seal in place, change the lifter settings to the default values
in the loader manager software and try doing a manual test run using the
loader manager software. Using one tube for this test run should suffice. 

Watch the tube travel up and down and ensure the settings are just high
enough to make the seal. When you stop getting that annoying beep, you are
making a proper air seal and the settings should be high enough. The
following is a description of lifter settings in case you have to tweak:

.	  Tube Lifter High Current Time (up and down):	The amount of time
the lifter travels at the high current setting (up or down) in increments of
tens of milliseconds

.	  Current Strength (These setting values do not represent any
particular unit of current measurement) 

o   High: The amount of current applied to the lifter motor during the
specified high current time (up or down). 

o   Low: The amount of current applied to the lifter motor (up or down)
between the end of the high current time and the reaching the lifter sensor
(upper or lower).

o   Final low: The amount of current applied to the lifter motor (up only)
after the lifter travels past the upper sensor


Also, check the straightness of the lifted test tube and where the top of
the lifter rod is stopping relative to the bottom of the sample probe. When
the test tube is in the up position and appears to be "leaning" relative to
the sample probe, the loader drawer may be misaligned. Please note; while
performing this test tube straightness check, it is important to ensure the
sample probe is straight. The sample probe straightness can be done visually
in situ, or when removed for the Calibur and rotated on its axis. Check how
square the loader drawer is relative the Calibur recess. 

If the test tube does not appear to be straight when lifted into place,
and/or if the drawer is not square, the lifter drawer may need to be
aligned.

The easiest fix is changing the seal and lowering the settings. If this
doesn't work the loader drawer may have to be aligned. If you need to do the
latter, please contact me directly and I can help further over the phone.

Ray


Raymond Lannigan

Cytek Development Inc.

540-832-2793

540-832-2794 (fax)

540-207-6709 (cell)

www.cytekdev.com


From: Paul Kron [mailto:pkron@uoguelph.ca] 
Sent: Tuesday, April 29, 2008 12:07 PM
To: cyto-inbox
Subject: Tube sticking on FACSCalibur


Hi everyone. I'm having a problem with the loader on a FACSCalibur, and I
would appreciate any suggestions. My apologies for the length.


Basic problem: When running racks using the loader, tubes keep sticking,
hanging from the SIP after the arm drops. This interrupts the run and
requires constant monitoring of the machine. This is not a "vertical motion"
error, but rather, a "tube stuck" error.


Some important background:

	    I have been using this machine, with this style of loader, for
over 6 years. We had the loader replaced last year, and the problem started
about 6 weeks after that. It was intermittent at first, but has become
worse. I am using the same types of sample tubes (Falcon), the same type of
loader seal (BD 19-66379-03), and the same basic procedures that I always
have. I have had occasional problems with tubes sticking in the past, and I
have always been able to resolve them by cleaning or replacing the loader
seal, and by stressing to users the importance of keeping the tops of the
tubes clean. These standard "fixes" are not helping in this case. I have
replaced the seal, which has resulted in a temporary improvement, only to
have the problem recur after a couple of days. If anything, I am being more
careful than usual about keeping the tops of the tubes clean. 


What's been tried:

	    When we had a BD technician in to do a 6 month maintenance, he
suggested using a different type of loader seal. I don't know the product
number offhand, but it was a combination of a thin, flat orange seal and a
black conical one. I tried this for a while, but the problem recurred. The
next time I contacted BD they suggested that I adjust the loader settings,
reducing the "high", "low" and "final low" settings by one (from 9 to 8, 8
to 7, and 7 to 6, respectively). I tried this, with the old style of seal
(the one I had used for the last 6 years), and it worked for 4 days. After
that, it became rapidly worse, until after a couple of more days, every tube
was sticking.


Theories:

	    It seems too coincidental that after years of use, this problem
started after a new loader was put in. The fact that there is a temporary
reduction in the problem when I change the seal suggests that the seal is
becoming damaged in some way, causing the tubes to stick, but this is
happening at an accelerated rate. I thought that the loader might simply be
"pushing too hard", creating too much pressure on the seal, but changing the
loader settings hasn't fixed this.  Is it possible that some kind of
alignment problem (i.e. the loader arm relative to the SIP) could cause this
to happen? 

	    I would be especially interested in any ideas about possible
causes of this problem. The suggestions we have received so far from BD have
been of the "what to try" kind, rather than the "what's causing it" kind. 


A comment on BD technical help:

	    We have generally been very happy with the support we receive
from BD. We have had some very skilled, very thorough technicians working on
this machine in the past. Unfortunately, the cost of anything but the most
basic service contract is out of our reach right now, and we would obviously
prefer to avoid a costly repair visit. 


Thanks for your help!




Paul Kron

Dept. of Integrative Biology

University of Guelph

Guelph, Ontario, Canada

pkron@uoguelph.ca