TM 10-6640-239-13 4-72 4-33.    CURBSIDE EXHAUST DAMPER MOTOR. This task consists of: a. Remove b. Install INITIAL SET-UP Tools Required General Mechanics Tool Kit, (Appendix B, Section III, Item 1) Materials/Parts Required Lockwashers (15) Equipment Condition Stool and Bracket Removed (Paragraph 4-40) General Safety Instructions WARNING ELECTRICAL SHOCK Before  performing  any  maintenance  actions  on  electrical  equipment,  ensure  all electrical power has been turned off.  Failure to comply with this warning may result in serious injury or death. REMOVE Remove Curbside Exhaust Damper Motor.  See Figure 4-21. a. Inside laboratory, remove drawers P3 and P4 to gain access to mounting hardware. b. Remove nine screws (1), lockwashers (2) and housing (3) covering damper housing (4).  Discard lockwashers. c. Remove cover from electrical junction box (5) located on bottom of motor (6).  Tag and disconnect motor leads and conduit (7). d. Remove six screws (8), washers (9), lockwashers (10), nuts (11), spacers (12), and damper assembly (13) with motor (6).  Discard lockwashers. INSTALL Install Curbside Exhaust Damper Motor.  See Figure 4-21. a. Install damper assembly (13) with motor (6) and secure with six screws (8), lockwashers (9), washers (10), nuts (11), and spacers (12). b. Connect conduit (7) and motor leads as tagged to electrical junction box (5).  Remove tags and install cover. c. Install housing (3) and secure with nine screws (1) and lockwashers (2). d. Install drawers P3 and P4. e. Install stool and bracket (paragraph 4-40).