TM   10-6640-216-13&P Table 2-11. Operator Preventive Maintenance Checks and Services - continued B - Before D - During Item No. 37 38 39 40 B Interval D A W M A - After W - Weekly Item to Be Inspected Copper Strip Corro- sion  Bath Gas-Oil Distillation Unit Explosion Proof Refri- gerator Field Testing  Kits Procedures Check for and have repaired or adjusted as necessary. a. b. a. b. a. b. a. b. Inspect  for  condition and  security. Check  operation. Inspect  for  condition and  security. Check  operation. Inspect  for  condition and security. Check  operation. Inspect   condition. Check  operation M - Monthly Equipment  is Not Ready/ Available If: Loose  or  missing fasteners. Copper  strip  corrosion bath  operates improperly. Loose  or  missing fasteners. Distillation  unit operates   improperly. Loose  or  missing fasteners. Refrigerator  is inoperative. Defective kits and missing  components. Kit will not perform test  properly. 2-29