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Home›Repair guides›Cummins/Onan›VR21 Replacement

Cummins/Onan — VR21 Replacement

Maintenance · Voltage regulator PC board

From a Cummins/Onan service manual covering: DL4, DL6, DL6T, DL6U. Check it applies to your exact model before use.

Applies to: Cummins/Onan DL4, Cummins/Onan DL6, Cummins/Onan DL6T

Before you start

  • The new printed circuit board might be damaged by malfunctioning components; do not install until all other problems are located and corrected.

Procedure

  1. Stop engine.
  2. Disconnect and label wires per AC control wiring diagram.
  3. Remove four screws at corners.
  4. Remove old PC board.
  5. Install new PC board; secure with four screws.
  6. Reconnect wires removed in step 2 at proper terminals.
  7. Place jumper W12 at proper terminals for the voltage code and connection.
  8. Standard regulator: turn R18 fully counterclockwise and R26 fully clockwise.
  9. Switching regulator: turn R5 and R36 fully clockwise.
  10. Perform voltage calibration and stability adjustment per Test P.

Full service-parts list: Cummins/Onan DL6 →

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.

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