ALTERNATOR7 AmpReconnect (-) negative (grounded) cable to battery post.If necessary, recharge battery with a battery charger, orby running engine 3 to 5 hours.NOTE: An isolation diode is not required if the equipmentmanufacturer routes the alternator output lead through aspecial ignition switch, which disconnects the alternatorwhen the switch is in the “OFF” position.WHEN CHECKING ALTERNATOR COMPONENTS,MAKE THE TESTS IN THE FOLLOWING SEQUENCE:Testing Isolation DiodeUnplug cap from fuseholder and connect small test lampbetween tip of white wire and battery negative terminal,as shown in Figure 190. Lamp should not light. If lamplights, isolation diode is defective. Now disconnect testlamp, and check continuity from the tip of white diodelead to tip of red diode lead with multimeter. The metershould show continuity in one direction and not in theother - reverse leads to check this, as shown in Figure191. If indication is incorrect, diode is defective andmust be replaced.Fig. 190 - Testing Isolation Diode SystemFig. 191 - Testing Isolation DiodeTesting for Shorts or Ground in Stator, Regulator orRectifierDisconnect charging lead from battery, and connectsmall test lamp in series between battery positiveterminal and fuse cap, as shown in Figure 192. (Testlead must not include an isolation diode.) DO NOTSTART ENGINE. Test lamp should not light. If it doeslight, stator or regulator or rectifier is defective. Unplugrectifier-regulator plug under blower housing. See Figure193. If test light goes out. rectifier or regulator isshorted. If test light does not go out, stator is grounded.Fig. 192 - Testing for ShortsFig. 193 - Regulator Rectifier PlugTesting StatorIf test indicates stator is grounded, look forobvious defects on leads. If bare leads are found, repairwith friction tape and shellac. If shorted leads are notvisible, replace stator. Stator should also be checked forcontinuity as follows: Use multimeter, set on resistancescale. Touch one test prod to lead at fuse holder. Touchother test prod to each of the four pins in plasticconnector. Unless the meter shows continuity at each ofthe four pins, the stator winding is open and the statormust be replaced. Figure 194.59
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