TM 10-6640-233-10 Table 2-12. Operator Preventive Maintenance Checks and Services (cont.) B - Before A - After M - Monthly D - During W - Weekly B D A W M 28 Oscilloscope Check operation. Refer to Oscilloscope is inop- applicable TM. erative. 29 Test Tube Mixer Check operation. Refer to Test tube mixer is applicable TM. inoperative. 30 Refrigerator a.   Inspect for security. Missing screws. b.   Check operation. Refer to Refrigerator is inop- applicable TM. erative. 31 Drying Oven a.   Inspect for security. Missing screws. b.   Check operation. Refer to Ovens are inopera- applicable TM. tive. 32 Ultrasonic Check operation. Refer to Inoperative ultra- Cleaner applicable TM. sonic cleaners. 33 Fluids Check for missing/damaged Components missing/ Contamination components. damaged. Set 34 Duplex Check operation of all compo- Inoperative compo- Ferrograph nents. Check for damaged fer- nents. Damaged System roscope and camera. lenses in ferroscope camera. 35 Flashpoint Check operation. Check for Components missing. Tester missing components. Refer to Inoperative flash- applicable TM. point tester. 36 Viscometer Set. Check operation. Refer to Inoperative viscome- applicable TM. ter set. INTERVAL ITEM NO. ITEM TO BE INSPECTED Equipment is Not Ready/ Available Procedures Check for and have repaired or adjusted as necessary. 2-24