Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Rectifier Test

NOTE: Alternator must be disassembled to inspect rectifier.

1. Use Rotunda 73 Digital Multimeter 105-00051, or equivalent, to check for continuity between positive diode leads and heat sink.
2. If continuity does not exist between any positive diode lead to heat sink, replace rectifier.
3. Reverse ohmmeter leads and check for continuity between negative diode leads and heat sink.
4. If continuity exists between any negative diode lead to heat sink, replace rectifier.
5. Check diode trio (smaller diodes between main diode leads) for continuity in both directions.
6. If any diode does not show continuity in one direction only, replace diode trio.