FACS 440 - can anyone help?

Raymond B. Hester (rhester@jaguar1.usouthal.edu)
Fri, 20 Oct 1995 11:19:44 -0500 (CDT)

This may be going above and beyond, but I'm desperate, so here goes...

Our FACS 440 has just developed a problem with the electronics carrying the
forward scatter signal and I wondered if anyone has any ideas about what
might be the problem.

If we select P1 (FALS) vs P2 (SS), or P1 vs any of the other parameters,
with the
calibrate signals (or beads or cells), on the dot display all one sees is
events on the Y axis (FALS on X axis, and the other parameter on the Y
axis).

The P1 signal does appear on the pulse display even though it doesn't
appear on the dot display.

If on the other hand one displays side scatter (P2) vs FL1, or any other
combination that does not involve P1, then the dot display is normal,
with dots appearing where you would expect them.

One final note. We have the forward angle scatter signal split between
P1 and P3 (so that we can still display P1 when we use it as a gating
parameter). If one chooses to display P3 (FALS via the "T") vs side
scatter (instead of P1 vs side scatter mentioned above), then the dot
display
appears normal. So it seems it has something to do with the P1 circuit.

And one (really) final note, if

P1 = FALS
P2 = SS
P4 = FL1
P5 = FL2 (we have a 5-parameter 440)

then turning the ADCs off and on produces the following results

Horizontal Vertical X ADC off Y ADC off

P1 P2 (signal in Y axis only) no signal no effect

P4 P2 (signal on X and Y axes) X signal only Y only

P4 P5 (signal in X and Y axes) no effect no signals

Any help us with this would be greatly appreciated.

Ray

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Raymond B. Hester, Ph.D.
Flow Cytometry Lab
The University of South Alabama Each day is a gift;
Mobile, AL 36688-0002 that's why it's called,
Email: rhester@jaguar1.usouthal.edu "the present".
Voice: (334) 460-6029 - Anonymous
FAX: (334) 460-6073
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


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