TM-10-3610-202-14 Table 4-1.  Organizational Preventive Maintenance Checks and Services Legend W - Weekly Q - Quarterly A-Annually H - Hours M - Monthly S - Semiannually B - Biennially MI - Miles For Readiness Interval Reporting Item Item To Be Equipment is Not No. W M Q S A B H MI Inspected Procedures Ready/Available If: 19 Shelter Door Filter Inspect for cleanliness, damage and proper installa- tion.  If necessary, clean filter as follows: Remove the filter by pulling the foam material from the frame. Clean by washing in a soap and water solution.  Dry thoroughly and spray with coater (NSN 4130-00-860- 0042). Install filter by inserting foam material under bottom lip of frame, then tucking it under remaining three lips of frame. 20 Ladder Inspect for damage and ensure that clamps are properly attached and are not damaged.  If inspection indicates that repair or replacement of the ladder is necessary, refer to para- graph 4-53. 21 Level Indicator Gages   Inspect the level gages for secure mounting, broken or cracked sight glass.  if inspection indicates that replacement of the level gages is necessary, refer to paragraph 4-55. 22 Fluorescent Lamps Inspect lamp for correct illumination.  If inspection indicates that replacement of the lamp is necessary, refer to paragraph 4-57. 23 Lamp Switches Inspect for proper operation, loose connections and excessive wear.  Inspect switch box cover for security of mounting.  If inspection indicates that replacement of a switch is necessary, refer to para- graph 4-59. 4-13