1. Troubleshooting Ground Relay Action
   1. Traction Motor Grounds
      1. Preparation for Meggering
      2. Meggering Traction Motors
      3. Using the locomotive microprocessor display to determine the origin of the ground relay.
      4. Maintenance practices that will help prevent ground relay (handout)
   2. Main Alternator Grounds
      1. Shorting the busses before meggering
      2. Meggering the Main Alternator field, and rotor
      3. Ground relay action caused by rectification diode failures
2. Dash 2 Loading Problems
   1. Causes of No Load
      1. Verifying GFC
      2. Loss of Reference String Voltage
      3. Loss of Sensor String Voltage
      4. Loss of Main Alternator Field
   2. Causes of Overloading
      1. Verifying Reference String Voltages
      2. Open Circuited Load Regulator
      3. Loss of Current or Voltage Feedbacks
      4. Overloadlng Caused by Intermittent Shorted SCR's
      5. Overloading Caused by Blown Bridge Diodes and Fuses
   3. Causes of Underloading
      1. Low Reference String Voltage
      2. Low Horsepower Caused by a Long Governor Balance Point
      3. Open SCR's
      4. Low Horsepower Caused by Incorrect Wheel Slip Action
3. 50 Series Loading Problems
   1. Causes of No Load
      1. Verifying GFC
      2. Loss of the #1 Power Supply
      3. Verification of Voltage to Test Point #5 of the Load Control Module
      4. Loss of the Sensor String
      5. Loss of Main Alternator Field
   2. Causes of Overloading
      1. Loss of, or Incorrect Voltage and Current Feedbacks to the Load Control Module
      2. Shorted Intermittent SCR's
   3. Causes of Underloading and Erratic Loading
      1. VerifyIng Power Supply Voltages
      2. VerifyIng Load Control Module Reference Voltage
      3. Incorrect Voltage and Current Feedback
      4. Low Horsepower Caused by a Long Governor's Balance Point
      5. Loading Problems Caused by the Wheel Creep's Radar System
      6. Loading Problems Caused by the Wheel Creep's Electromotive Force per Revolution Module
      7. Open SCR's
      8. Defective Excitation Limit Function
      9. Barometric Compensation Module
4. 60 Series Loading Problems
   1. Causes of No Load
      1. Verifying GFC Through the IOL Data Packs Screen
      2. Qualifying the Power Supply Voltages, Short Circuit Protection, and Open Circuit Protection
      3. Checking for a Defective Logic CPU
      4. Checking for a Defective Excitation CPU
      5. Verification of SCR Gating Voltages to the Firing Circuit
      6. Synchronization Module
      7. No Common Memory Communication
   2. Causes of Overloading
      1. The Loss of, or Incorrect Voltage and Current Feedbacks Into the Excitation System to the Microprocessor
      2. Shorted Intermittent SCR's
      3. Defective Excitation Microprocessor
   3. Causes of Underloading and Erratic Loading
      1. Qualification of the Power Suppiy for Voltages, Noise, and Defective Plug Receptacles
      2. Incorrect Voltage and Current Feedbacks
      3. Faulty Analog to Digital Processing
      4. Defective Excitation Microprocessor
      5. Defective Radar Circuitry, or Processing
      6. Low Horsepower Caused by a Long Governor's Balance Point
5. Troubleshooting Dynamic Brake
   1. Troubleshooting Field Current Excitation
      1. Verification of the Dynamic Brake Handle Signal Into the Rate Control Module on Dash 2 Locomotives
      2. Verification of the Dynamic Brake Handle Signal Into the Load Control Module on 50 Series Locomotives
      3. Verification of the Dynamic Brake Handle Signal Into the Display on 60 Series Locomotives
      4. Checking Field Current Umits on 40, 50, and 60 Series Locomotives
   2. Qualification of Dynamic Brake Regulation, and Protection
      1. Using an MG Set to Verify Regulation and Protection Limits on 40 Series Locomotives
      2. Using a Power Supply to Verify Protection and Regulation
      3. Limits on 50 Series Locomotives; Using the Display to Troubleshoot Regulation Problems on 60 Series Locomotives
      4. Qualification of Dynamic Brake Grid Protection
      5. Grid Open Circuit Protection
      6. Checking for Grounded Grids

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