TM 1-1520-238-T-4 Change 5 6–82.21 6–22.1. HOD NGB 2 READING – DISPLAYS –31 C TEMPERATURE 6–22.1 Tools: Nomenclature Part Number Tool Kit, Electrical SC518099CLA06 Repairer’s Multimeter, Digital AN/PSM-45 Personnel Required: 68X Armament/Electrical Systems Repairer One person to assist References: TM 1-1520-238-23 TM 55-1500-323-24 TM 9-1230-476-20-2 Equipment Conditions: Ref Condition TM 1-1520-238-23 Access provisions – R200 access panel and RN6, R60 fairings open. WARNING Turn off power before detaching or attaching wires and connectors. High current 28 VDC or 115 VAC is present. Failure to do so could result in death or serious injury. NOTE A –32 C reading is caused by no power to the transducer (MT16) or no signal from the transducer to the MRTU TYPE 1 (A62). If all HOD temperatures are –32 C and ENG START circuit breaker is open, troubleshoot with paragraph 6–22.2 before proceeding. Entry in ( ) following pin locations is multimeter lead orientation. 1. Detach P60. Check for open between: P60–F and P60–G (red/blk), P60–J and P60–H (blk/red). YES Go to step 3. NO Go to step 2. 2. Check for short between: P60–F and ground, P60–H and ground. Does short exist? YES Go to step 3. NO Go to step 4. 3. Locate open or short in the wire harness between P60 and MT16. Can wire harness be repaired? YES Repair wiring (TM 55-1500-323-24). Go to paragraph 6–13. NO Replace MT16 (TM 1-1520-238-23). Go to paragraph 6–13. 4. Detach P672. Check for short between: P672–87 and ground. Does short exist? YES Repair shorted wire between: P672–87 and ground (TM 55-1500-323-24). Go to paragraph 6–13. NO Go to step 5. 5. Reconnect P60. Check for open between: P672–86 and P672–87 (blk/red). Does open exist? YES Repair open wire (TM 55-1500-323-24). Go to paragraph 6–13. NO Refer to TM 9-1230-476-20-2 to troubleshoot multiplex subsystem. END OF TASK