Technote #
38 Sample Probe is stuck in the down position.
Date Updated Category
20-08-07 System Operation
[STarStation 2.0][STarStation 2.3]


The probe being stuck in the down position is a common symptom of a sample arm that is adjusted too low or does not have a clear path to the bottom of a well. The arm incorporates an optical switch at the top of the linkage inside the instrument. If the tip of the sample probe hits a solid surface before the top of the arm travels low enough to trip the switch, both the arm and the software freeze. The system monitor will indicate "Busy".

Follow these steps:

1) Remove the blue light from above the sample arm.
2) Unscrew the brown knurled tubing connector that connects the sample tubing to the top of the sample arm. This will allow the probe extra room to manoeuvre and will most likely allow the sample arm to raise back up.

3) Gently try to raise the sample arm assembly. If this is difficult remove the sample needle.
4) In STarStation, abort acquisition.

5) Once the sample has cancelled and the instrument is idle, replace the sample tubing and blue light and proceed with the adjustment of the sample arm. See Technote #40

6) If the software becomes locked or unresponsive, switch STarStation software off and then relaunch it. If StarStation is unable to connect to the cytometer because the cytometer is in a "BUSY" state, cycle the power to the LX100/200. Ensure that the sample needle is NOT in the down position (inside the XYP) before you cycle the power on the instrument or restart the software

7) To make sure the sample arm is moving successfully before continuing with your samples, run a calibration or an acquisition with a well containing water. (The optical switch is only incorporated in a calibration or sample acquisition function. It cannot be tested with a wash or other maintenance operation. Fill the well with water to prevent air from being acquired.) or raise and lower the sample probe several times using the functions on the control tab of the STarStation instrument controls


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