TM 5-3810-306-34
TABLE 3-1. DIRECT AND GENERAL SUPPORT TROUBLESHOOTING (CONTD)
Malfunction
Test or Inspection
Corrective Action
Step 3. Check voltage between Pin 8 and Pin 11 on CPU terminal board, terminal block X1. (Refer to page 3-75.)
Reading should be: -5 Vdc. If OK go to Step 4.
a.
Step 4. Check voltage between Pin 1 and Pin 3 on terminal block in cable reel. (Refer to page 3-76.) Reading should be:
-5 Vdc. If OK go to Step 5.
a.
Faulty wiring between CPU and length transducer. Repair as necessary.
Step 5. Check voltage between Pin 2 and Pin 1 on terminal block in cable reel. (Refer to page 3-77.) Readings should
be:
Boom retracted = - 0.5 Vdc
Boom extended = -2.27 Vdc
If OK go to Step 6.
a.
Step 6. Check voltage between Pin 8 and Pin 10 on CPU terminal board, terminal block X1. (Refer to page 3-78.)
Readings should be:
Boom retracted = - 0.5 Vdc
Boom extended = -2.27 Vdc
If OK go to Step 7.
a.
Faulty wiring between CPU and length transducer. Repair as necessary.
Step 7. Check voltage between test points MP15 and MP6 on CPU main board. (Refer to page 3-79.) Reading should
be: +0.5 Vdc. If OK go to Step 8.
a. Replace CPU if reading is not as above. ( Refer to page 14-4.)
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