Cummins/Onan — Flashing the Field (Test D)
Repair & overhaul · exciter field
From a Cummins/Onan service manual covering: DL4, DL6, DL6T. Check it applies to your exact model before use.
Applies to: Cummins/Onan DL4, Cummins/Onan DL6, Cummins/Onan DL6T
Before you start
- Incorrect flashing procedure can damage the voltage regulator. Do not keep excitation circuitry connected longer than 5 seconds.
Procedure
- Assemble a 6-volt battery, 10-ohm resistor, and diode as shown.
- Start the generator set and operate at normal rpm.
- Touch the positive (+) lead to terminal TB2-4 and the negative (-) lead to terminal TB2-5.
- Hold leads on terminals just long enough for voltage to build up.
Tools required
- 6-volt battery (or 12/24V set battery) Amazon
- 10-ohm resistor (20-ohm for 12V, 40-ohm for 24V) Amazon
- diode (300 V, 12 amp) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.