TABLE 3-1. DIRECT AND GENERAL SUPPORT TROUBLESHOOTING (CONTD)
Test or Inspection
Damaged length cable. Replace length cable. (Refer to page 14-16.)
Step 5. Check ohm reading between wire disconnected from Pin 35 and Pin 34 at CPU terminal board, terminal block X1.
Anti-Two-Block Switch Closed = 4700 ohms + 500 ohms
Anti-Two-Block Switch Open = greater than 1 megaohm
If OK go to Step 6.
Faulty wire between cable reel and CPU. Repair as necessary.
Step 6. Check CPU main board function by installing a temporary resistor (4700 Ohm) at terminal block X1 between Pin
35 and Pin 34. (Refer to page 3-73.) With resistor connected, alarm should be inactive. If OK go to Step 7.
Step 7. Bad data transfer between CPU and console.
Refer to malfunction No. 87.
LENGTH READING INCORRECT
Step 1. Check that length potentiometer in cable reel, with boom fully retracted, is adjusted counterclockwise to stop.
Adjust length potentiometer counterclockwise to stop.
Step 2. Extend and retract boom to ensure clutch in big gear wheel of length transducer is not slipping on potentiometer
axle in cable reel. (Refer to page 3-74.) If OK go to Step 3.