TM  10-6640-215-13 3-4. REMOVE/INSTALL FLUORESCENT LIGHT FIXTURE LAMP AND STARTER - continued. a. Align new starter prongs with starter slots in light fixture. b. Insert new starter into slots and rotate 90 degrees. c. Install lamp diffuser and secure diffuser to lamp fixture with four captive screws. d. Place appropriate circuit breaker in the ON position. NOTE Procedures for removing and installing fluorescent lamps and lamp starters in the emergency light fixtures DS7 and DS13 are identical to the procedures outlined in paragraph 3-4.  To test the emergency lights, place the main circuit breaker A1CBl in the OFF position.  Emergency lights should come on. 3-5.    REMOVE/INSTALL PURGE INTAKE DOOR FILTERS. This task consists of: a. Removal b. Installation INITIAL SET-UP: Tools Required General Mechanics Tool Kit, (Appendix B, Section III, Item 2) Materials/Parts Required Lockwasher, (Appendix F) REMOVAL Remove Purge Door Filter.  See figure 3-2. a. Unlatch and open purge door if required. b. Remove four screws and four lockwashers from purge door screen.  Remove screen and dirty filter. INSTALLATION Install purge door filter. a. Install a cleaned or new filter. 3-18