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The Perfect Focus System (PFS) keeps the microscope in focus by constantly correcting the distance between the specimen and objective lens. All the objective lenses on GFP3 except the 4x are compatible with the PFS, although the 60x oil lens must be used with a glass-bottomed imaging vessel containing aqueous medium. Make sure the specimen is in focus. Check that the amber DM IN/OUT light on the PFS Offset Controller is on. Check that the ‘Focus’ LED on the front operation panel is on. Press the ON button next to the LED. It should emit two tones and go solid green. Readjust the focus if necessary using the wheel on the PFS Offset Controller.
If the ON button flashes green and emits several short tones the PFS is not working for some reason. Check that you aren’t using the 4x lens, that the specimen is in focus, the dichroic mirror is in position and the ‘Focus’ LED is on. If they are all correct then for some reason the specimen is not compatible.
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