Light source is the hardware backbone of the 3D-PTV experiment. Sporadic problem of shutting down the laser during an experiment and/or malfunctioning from the very beginning inspire one to unveil the problem and fix the error.
Frequently encountered problems include when flow rate is inadequate,cover interlock and auxiliary interlock are open.
Specifically what triggers the laser shut down can be figured out from the Interlock STATUS indicators warning displayed on the Remote Control Module shown below.
Here is the pictorial demonstration that will guide one to address the problem and the way to solve it.
Flow indicator is on
Here one point is worth mentioning regarding the yellow key. This key has to be carefully press down and then twist in a fashion such that it acts as a proxy cover interlock switch in the laser head.
The last picture in the image matrix above makes the laser fully naked and its time to find out a tiny little screw in a horde of electronic circuits.
The figures above are taken from slightly different angle trying to throw light on the very little part of interest where the desired screw is staying. The screw is almost obscure but one easy way to detect it is to focus on the warranty seal where it is written "WARRANTY VOID IF THE SEAL IS BROKEN" with Spectra Physics trademark. Here is the magnified view for better observation.
After learning where the screw is,one has to gently move the screw head anti clockwise and about half a rotation.
That should eventually switch off the glow of the flow indicator on the control module and make the laser ready to shoot.
Cover indicator is on
Cover indicator glows when the cover interlock switch in the laser head or power supply is on and one can heal the problem by opening the small window on the big hatch on the far left side where BeamLok is marked on it. This window should close down in such a way that the extruded part from it comes down pushes the black button properly. (One can remember that yellow key did the same job while discussing the flow indicator problem)
Auxiliary indicator is on
Auxiliary indicator glows when the auxiliary interlock circuit is open. The auxiliary interlock connector (AUX INTLK) is located on the connector panel of the power supply. Often this AUX indicator also glows if the cable on the cooler is displaced/disturbed due to careless movement near the cooler. Taking out the cable or tighten it a bit can help to solve the problem.
