Cummins/Onan — Replacing Diodes (Rotating Rectifier Assembly)
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DQAD, Cummins/Onan DQAE, Cummins/Onan DQAF
Before you start
- Layers of dust can cause diodes to overheat and fail. Brush dust off regularly.
Procedure
- Make sure the replacement diode is of the correct polarity.
- Disconnect the pigtail from the terminal post and unscrew the old diode.
- Apply heat-sink compound under the head of the diode; do not get it on the threads.
- Torque the diodes to 36 to 42 in-lbs (4 to 4.8 N-m).
- Torque the pigtail terminals to 24 in-lbs (2.7 N-m) when reassembling.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Diode torque 36 to 42 in-lbs (4 to 4.8 N-m)
- Pigtail terminal torque 24 in-lbs (2.7 N-m)
Full service-parts list: Cummins/Onan DQAD →, Cummins/Onan DQAE →, Cummins/Onan DQAF →
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.