Section 378 (Charging System - Generators & Regulators): Generator: Inspection

1. Using an ohmmeter, check the continuity between terminals F and B.
   Fig 1: Checking Voltage Regulator Continuity

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   1. Standard: 
   2. When the positive and negative poles between terminals F and B are exchanged, there is continuity in one way but no continuity in another way. 

   If the continuity is not as specified, replace the regulator.

2. Using an ohmmeter, check the continuity between terminals F and E.
   Fig 2: Checking Voltage Regulator Continuity

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Standard: 
   2. When the positive and negative poles between terminals F and B are exchanged, there is continuity in one direction, but no continuity in the other. 

If the continuity is not as specified, replace the regulator.

1. Inspect the rotor for open circuit.
   Fig 3: Inspecting Rotor For Open Circuit

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   Using an ohmmeter, check that there is continuity between the slip rings.

   Standard resistance: 2.1 - 2.5 Ohms at 20°C (68°F) 

   If there is no continuity, replace the rotor.

2. Inspect the rotor for ground.
   Fig 4: Inspecting Rotor For Ground Using Ohmmeter

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   Using a ohmmeter, check that there is no continuity between the slip ring and rotor.

   If there is continuity, replace the rotor.

3. Check that the slip rings are not rough or scored.

   If rough or scored, replace the rotor.

4. Using vernier calipers, measure the slip ring diameter.
   Fig 5: Using Vernier Calipers To Measure Slip Ring Diameter

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   1. Standard diameter: 14.2-14.4 mm (0.559-0.567 in.) 
   2. Minimum diameter: 12.8 mm (0.504 in.) 

If the diameter is less than minimum, replace the rotor.

1. Inspect the stator for open circuit. Using an ohmmeter, check that there is continuity between the coil leads.
   Fig 6: Inspecting Stator For Open Circuit Using An Ohmmeter

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   If there is no continuity, replace the drive end frame assembly.

2. Inspect the stator for ground. Using an ohmmeter, check that there is no continuity, replace the drive end frame assembly.
   Fig 7: Checking For No Continuity Using An Ohmmeter

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   If there is no continuity, replace the drive end frame assembly.

Using a vernier caliper, measure the exposed brush length.

Fig 8: Using A Vernier Caliper To Measure Exposed Brush Length

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1. Standard exposed length: 10.5 mm (0.413 in.) 
2. Minimum exposed length: 1.5 mm (0.059 in.) 

If the exposed length is less than minimum, replace the brushes and brush holder assembly.

Fig 9: Inspecting Rectifiers (Rectifier Holder) Using Ohmmeter
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1. Check the positive (+) rectifier.
   1. Using an ohmmeter, connect one tester probe to the positive (+) terminal and the other to each rectifier terminal.
   2. Reverse the polarity of the tester probes and repeat step  a.
   3. Check that one shows continuity and the other shows no continuity.

   If the continuity is not as specified, replace the rectifier holder.

2. Check the negative (-) rectifire.
   1. Using an ohmmeter, connect one tester probe to each negative (-) terminal and the other to each rectifier terminal.
      Fig 10: Checking Negative Terminal (-) Using Ohmmeter

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   2. Reverse the polarity of the tester probes and repeat step  a.
   3. Check that one shows continuity and the other shows no continuity.

   If the continuity is not as specified, replace the rectifier holder.

Check that bearing is not rough or worn.

If necessary, replace the bearing (See REPLACEMENT ).