Cummins/Onan — Flashing Field (Section I)
Repair & overhaul · Exciter field
From a Cummins/Onan service manual covering: 300.0 DFT, 350.0 DFU, 350.0 WF, 400.0 DFV, 400.0 WK, 450.0 DFW, 500.0 DFY, 600.0 DWV. Check it applies to your exact model before use.
Applies to: Cummins/Onan YB series
Before you start
- High voltage will be present on voltage regulator terminals if output builds up.
- Do not keep field flashing circuitry connected longer than 5 seconds or damage may occur.
Procedure
- Assemble six-volt supply, resistor, and diode as shown in Figure 3.
- Remove frontal grille to access voltage regulator.
- Disconnect lead F1 at VR1-3.
- Start unit.
- Touch positive lead of supply to F1 and negative to VR1-2.
- Hold leads until voltage starts building.
- Shut down unit and reconnect wires.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Do not keep field flashing circuitry connected longer than 5 seconds.
Full service-parts list: Cummins/Onan YB series →
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.