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o You are strongly advised to set both sensitivity / high voltage controls to no more than 20% of
their travel and to keep the light level relatively low during these checks. This will be sufficient
to show correct operation without damaging the detectors.
o Remove each detector cable from the rear of the controller, and inspect the plugs for bent or
missing pins: there should be 8 pins visible in each mini-DIN plug. Re-connect the plugs into
the controller and ensure that each one is pushed fully home; there should be no significant
resistance when the plugs are inserted into their sockets.
o Check both the detector cables for damage.
o Open the filter cube door and remove the filter cube. Check the O-ring around the door to see
that it is properly seated in its groove, and look at the top left corner of the opening to locate the
door-sensing micro-switch. There should be no debris or dirt around the micro-switch, and no
damage to the small actuating arm. Re-close the door and screw it shut securely until there is
no gap between the door and the optical block body. Re-check to see if correct function is
restored.
o Cycle the lever control on the front of the optical block to move the laser / visible dichroic in and
out of the beam path. The motion should be free and un-impeded. Move the lever to the right
(fully clockwise). This should de-activate the interlock. Check to see if correct function is
restored.
o If none of these checks are successful in restoring operation, try the checks in the following
section, but apply them to both detector modules.
No high-voltage reading on one detector whilst the second detector is fully functional.
Probable cause: faulty interlock signal contacts on one detector module.
o As for the previous tests, check the cable and the connector for the offending detector module
and verify that there has been no damage.
o Turn off the controller and un-plug both detectors from it.
o Follow the procedure in the appendix for removing the offending detector module.
o Inspect the spring contacts in the small slot in front of the detector module: they should be un-
distorted, clean and clear of debris / dirt and positioned along the centre of the slot.
o Inspect the contact pins which emerge from the optical block. These should be clean and free
of any debris. They can be cleaned using a lint-free tissue or cotton swab soaked in a little
isopropyl alcohol or industrial methylated spirit. Do not use a more aggressive solvent (no
acetone or chlorinated solvents).
o Check that the filter cube door is fully closed, and that the visible / infrared dichroic mirror is in
the beam (actuator moved fully clockwise). Using a multi-meter set for resistance or continuity
measurement check the resistance between the outer contacts on the main optical block: there
should be a very low resistance reading (sub 1 Ohm).
o Follow the procedure in the appendix for replacing the offending detector module, paying
special attention to the alignment of the module with respect to the top of the optical block.
o Check to see that correct function is restored. If you have no success, the fault may lie
elsewhere: contact Scientifica for assistance.
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