Cummins/Onan — Rectifier Testing - Method B (120-volt AC Tester)
Testing & diagnosis
From a Cummins/Onan service manual covering: 02SX1N1A, 04SX1N, 04SX1N1A, 04SX1N1B, 04SX1N2B, 04SX1N3B, 04SX1N4B, 06SX1N, 06SX1N1A, 06SX1N1B, 06SX1N2B, 06SX1N3B…. Check it applies to your exact model before use.
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Before you start
- Avoid grounding the hot lead of a tester when checking a Magneciter component installed on a generator.
Procedure
- Make certain no component part of Magneciter is electrically grounded.
- Isolate rectifier by disconnecting one end from its point of connection.
- Connect two test leads together and observe brilliance of bulb (lead resistance only).
- Connect test leads to rectifier and observe brilliance of bulb.
- Good if bulb lights with low intensity.
- Defective if bulb lights high intensity (short) or fails to light (open); replace rectifier.
- Be sure to install rectifier in proper direction per wiring diagram.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.