Macrosort head corrosion - summary

From: Barsky, Lora (LBarsky@chla.usc.edu)
Date: Mon Sep 16 2002 - 16:25:10 EST


Thank you to all who sent me email regarding this.  I now have a new head
and it hasn't been damaged.  My field engineer did two things,  he installed
a new head and also replaced the high voltage board, deep in the card cage.
We don't know if the board helped to cause our problem yet, but what we do
know is what I was seeing was the result of electrolysis.  Apparently,
electric charge from the deflection plates was traveling up the stream and
causing the stainless steel to deplate.  This can be avoided, I've learned,
by making sure that the macrosort head platform appears to be flat, or level
before putting the nozzle on.  Then put the nozzle on and adjust it's
trajectory with the "nozzle tool".  Once you've got it into the catcher and
it looks good, side to side and front to back,  turn on the plates and walk
the stream into the catcher if it moved out, with the center stream control
knob.  Go and do the normal alignment stuff and tweek theta and alpha if you
need to move the stream in the laser spot to get more signal.

My situation was repeated by another lab and a head was damaged in less than
a day.  The lab purposefully aimed the stream at a plate, max-ed the charge
voltage and ended up with exactly what happened to my lab, but a lot
quicker.

To answer a question regarding the name of the head, yes it is called
Macrosort and it does ship with a 70um and a 400um nozzle and it is the head
that Turbo sort machines use.

Thanks again to all concerned,


Lora W. Barsky
Childrens Hospital Los Angeles
4650 Sunset Blvd.  Mail Stop #62
Los Angeles,  CA   90027

323-669-5935 PHONE
323-660-1904 FAX



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