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Check that the transmitted light illumination arm in the vertical position and is not pushed back to allow easy access to the stage. Check that the objective lens turret is correctly in position (i.e. the objective lenses are not halfway between one position and another). The interlock engages when the system is not laser-safe and there is a risk of laser light entering the user's eyes. Putting the above components back into their safe position should clear the interlock condition.
SPE and SPE2: The focus won't go up any further than a certain height so you can't get your specimen in focus
This is most likely caused by somebody either deliberately or accidentally engaging the Focus Stop. If you look at the focus wheel on the right of the stand you will see a narrow Focus Stop wheel between the focus wheel and the body of the microscope. It has two arrows saying Adjust and Set. Rotate the wheel in the Adjust direction and this will disengage the Focus Stop.
If you ever need to use the Focus Stop for any reason please disengage it once you have finished. Also please be careful not to accidentally engage the Focus Stop when you are adjusting the focus knob.