Diagnosable remotely - YES
Fixable remotely - YES
There are several possible reasons why no particles appear on the ZetaView screen, despite PS100 or a known sample with particles being injected into the measuring cell. Almost all of these can be checked either by the customer themselves with guidance, or by an engineer logging in remotely. If none of the below solutions work, consult with PMX.
Wrong cell calibration file:
**Only applies to software version v8.04.02_SP2 and earlier**
This and earlier versions of the software used a manual calibration file change to switch between fluroescence and scatter modes, as well as between different cell assemblies if the customer has more than one.
SOLUTION - check the correct calibration file is selected (for scatter mode, the file without -FLUOR label).
Fluorescence filter is engaged:
Check that the fluorescence filter is not engaged, which will cause no particles to be visible with PS100 or unlabelled samples.
SOLUTION 1 (Instruments with a manual filter) - check the filter is not in place. It should be pulled down, not pushed upwards.
SOLUTION 2 (Instruments with an automated filter) - check the filter has not been accidently activated in the software. "Scatter (None)" should be the option selected.
Misalignment of the laser and microscope (out of focus):
The optics have become misaligned and the particle are so out of focus that they cannot be seen.
SOLUTION - go through the stages of re-focussing as detailed in the Solution Guide "ZetaView - Particles Out of Focus".
Measurment cell is not orientated correctly:
**Z-NTA instruments only**
It is possible the cell could have been placed back into the cell assembly the wrong way around, for example, after being removed for cleaning.
SOLUTION - check the cell is orientated correctly into the carrier and holder. The laser window should be on top, and the microscope window should be facing the ZetaView instrument, shown below.
Laser not operational:
This is a very unlikely scenario, but theoretically possible. To check whether the laser is active or not, slide a piece of white paper into the gap above the cell assembly, between the CA and the silver front plate. If the laser is shining, you should see the laser light being reflected, shown below.
SOLUTION - there is no reason why the laser would be off. Contact PMX Support for advice.
Incorrect laser timing:
This is again an unlikely scenario, but can be checked if all other options are exhausted. Check the laser timing by clicking on the camera button in the "Cell Check" tab, then under the "Laser Timing" sub-tab, check which setting is active.
SOLUTION - the correct setting is "Camera Frequency, Laser Pulse Duration = Shutter Duration". If this is not selected, change to this option.
