Cummins/Onan — Flashing The Exciter Field
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Incorrect flashing procedure can damage the voltage regulator.
- HAZARDOUS VOLTAGE. Touching uninsulated high voltage parts inside the control box can result in severe personal injury or death.
Procedure
- Refer to Figure 5-2 to locate appropriate terminals for battery lead connection.
- Use a six volt dry cell battery with two clip leads and a 12 amp, 300 volt diode.
- If six volt battery not available, use 12 volt automotive battery with 20-ohm resistor in series, or 24 volt battery with 40-ohm resistance.
- After starting engine, touch positive (+) battery lead to TB1-4 or PIN 8, and negative (-) lead to TB1-5 or PIN 7 until voltage starts to build up.
Tools required
- six volt dry cell battery Amazon
- two clip leads Amazon
- 12 amp, 300 volt diode Amazon
- 20-ohm resistor Amazon
- 40-ohm resistor Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Do not keep excitation circuitry connected longer than five seconds.
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.