NEC P452H User Manual page 131

(2) Vacuum off accumulated dust and dirt on inside and outside of
the filter case.
(3) Fix a new Filter (B) onto the filter case.
4. Remove the lamp housing.
(1) Loosen the three screws securing the lamp housing until the
phillips screwdriver goes into a freewheeling condition.
• The three screws are not removable.
(2) Remove the lamp housing by holding it.
CAUTION:
Make sure that the lamp housing is cool enough to before
removing it.
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8. Maintenance