TM 5-6350-264-14&P-10 NAVELEX EE 181-AA-OMI-110/E121 C-9412 T.O.  31S9-2FSS9-1-10 (7) Inspect varistors for evidence of physical damage or overheating. Check varistors by disconnecting one lead of each varistor from TB1.  Set multimeter to ohms and connect meter leads to varistor.  Meter should indicate over 100,000 ohms. f. Refer to figures 5-1, 5-2, 5-3, 5-4, and FO-1 and table 5-1 for maintenance controls, parts locations and identification, and wiring diagram and test points referred to in table 5-2 troubleshooting procedures. NOTE Before you use table 5-2, be sure you have performed all applicable operating checks. WARNING The Audible Alarm presents a noise hazard to personnel in the area.  It must be disabled before any troubleshooting procedures are attempted. g. Disable the Audible Alarm.  To Disable The Audible Alarm (AA) for maintenance or troubleshooting, notify proper authorities per installation/site security procedures.  Enter the Control Unit area and turn the operating mode switch (key operated) to TEST/RESET position. If the Control Unit audible signal device sounds, ignore it for the moment.  Inspect the Control Unit door to ensure it is flat, straight, and completely closed.  Open the door, pull the TAS plunger all the way out, and ensure there is no debris between the door and enclosure.  There are six LED’s on PC board A12 in the upper right comer of the Control Unit.  Note any of these LED’s that are on.  To locate the source of an alarm, turn the mode switch to TEST/RESET, unlock and open the door.  Look at the LED’s in the upper right corner of the CU.  Each detector is connected to one LED. The first alarm signal received at the CU will light the LED connected to the detector that originated the alarm. (1) If the AA is silenced, don ear protection and open the AA door.  Pull the TAS plunger all the way out, remove screws that secure the faceplate, and remove the faceplate. The power switch is in the upper left corner of the AA; turn it off. (2) If the AA continues to sound, tag, remove, and isolate the green wire (from status processor) from TB4-1 in the Control Unit.  Install a jumper between TB4-4 and 1.  AA should be off.  Don ear protection and open the AA door.  Pull the TAS plunger all the way out, remove screws that secure the faceplate, and remove the faceplate.  The power switch is in the upper left corner of the AA; turn it off. (3) In the Control Unit, remove interconnecting wire from AA from TB4-3, and connect a jumper wire between TB44 and 3.  The AA is now disabled; however, for safety it should be treated as if it were on.  Remove jumper from TB4-4 and 1. 5-4. TROUBLESHOOTING PROCEDURES. WARNING HIGH VOLTAGE is used in the operation of this equipment.  DEATH ON CONTACT may result if personnel fail to observe safety precautions.  Learn the areas containing high voltage in each piece of equipment.  Be careful not to contact high- Voltage connections when installing or operating this equipment.  Never work on electronic equipment unless there is another person nearby who is familiar with the hazards of the equipment and competent in administering first aid. 5-2