TM 5-6350-275-24&P
Table 3-9. Sensors DS Maintenance Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. MICROWAVE MOTION SENSOR FAILURE (Figure 3-14)
Step 1. Perform a walk test (per the SAIG) of sensor unit by moving toward sensor unit and monitoring LED
indicator. The green LED should always be illuminated until you begin walk test. The red LED lamp
should illuminate when you have taken two to four steps within detection area.
If red LED does not illuminate, go to step 2.
Step 2. Remove outer case from sensor assembly (1 or 3 depending on type of sensor assembly) and check
fuse located on PWA (2 or 6).
If fuse is blown, replace fuse and conduct a walk test.
If walk test checks good, replace cover assembly; MMS is good.
If fuse is not blown, go to step 3.
Step 3. Depending on series of sensor, check for following input power voltages at TB (5). For HITECH ac/dc
series sensor, set to multimeter to read vac. Place leads across pins 2 and 3 on terminal board. The
multimeter should indicate 12 vac. IF a dc input is used, set multimeter to read vdc and place negative
lead on TB pin 4 and positive lead on pin 5. multimeter should read +10 to +20 v.
For HITECH ac series sensor, check for 9 to 15 vac across pins 2 and 3 of terminal board.
For HITECH dc series sensor, check for +10 to +20 v by placing negative lead on pin 2 and positive lead
on pin 3 of terminal board.
If voltage is present on terminal board, replace Microwave Motion Sensor Assembly (Para. 3-119 or 3-
120).
If voltage is not present on terminal board, check input power source and wiring. Replace as necessary.
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