RADIO GP 3E7140 - Caterpillar

Table 1
Tools Needed(1)
Caterpillar Part Number Part Name Quantity
6V-7070 Digital Multimeter 1
146-4080 Digital Multimeter
(RS-232) 1
(1) Only one multimeter is needed for this test.
Illustration 1 g00775020
Rectifier Block
(1) "AC1" terminal
(2) "AC2" terminal
(3) "AC3" terminal
(4) Negative terminal
(5) Positive terminal Perform the following steps in order to test the rectifier block. When possible, use the diode test scale. If there is no diode test scale, use the resistance scale.
Touch the red ohmmeter lead to the rectifier terminal that is marked "+".
Touch the black ohmmeter lead to the rectifier terminals that have the following labels: "AC1", "AC2" and "AC3". The meter should indicate an open circuit or high resistance for each rectifier terminal. If the meter does not indicate an open circuit or high resistance, the rectifier is bad. Replace the rectifier.
Touch the black ohmmeter lead to the rectifier terminal that is marked "+".
Touch the red ohmmeter lead to the rectifier terminals that have the following labels: "AC1", "AC2" and "AC3". The meter should indicate a good diode or low resistance. If the meter does not indicate a good diode or low resistance, the rectifier is bad. Replace the rectifier.
Touch the black ohmmeter lead to the rectifier terminal that is marked "−".
Touch the red ohmmeter lead to the rectifier terminals that have the following labels: "AC1", "AC2" and "AC3". The meter should indicate an open circuit or high resistance for each rectifier terminal. If the meter does not indicate an open circuit or high resistance, the rectifier is bad. Replace the rectifier.
Touch the red ohmmeter lead to the rectifier terminal that is marked "−".
Touch the black ohmmeter lead to the rectifier terminals that have the following labels: "AC1", "AC2" and "AC3". The meter should indicate a good diode or low resistance. If the meter does not indicate a good diode or low resistance, the rectifier is bad. Replace the rectifier.