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Diode Trio Test

  1. Remove diode trio from end frame. Connect an ohmmeter to single connector and to one of the 3 connectors. See Fig 1. Note reading and reverse leads. If readings are the same, replace diode trio.
  2. A good diode trio will give a high and low reading. Repeat tests between single connector and each of the 3 connectors. Connect ohmmeter to each of the 3 connectors. If any readings are zero, replace diode trio.
NOTE: Before replacing diode trio, also check rectifier bridge. Do not use high voltage, such as 110-volt test lamp, when testing diode trio.
Fig 1: Bench Testing Diode Trio
G11704Courtesy of GENERAL MOTORS CORP.
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