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Home›Repair guides›Field Flashing Procedure for Voltage Regulator

Cummins/Onan — Field Flashing Procedure for Voltage Regulator

For these Cummins/Onan models: MDTNDTA, PROTEC series, SK, Standard YD Generator and Regulator, YD PTO.

Applies to: Cummins Onan Mdtndta, Cummins Onan Protec Series, Cummins Onan Standard Yd Generator And Regulator, Cummins Onan Yd Pto

Before you start

  • WARNING: Be cautious when working on a generator that is running to avoid electrical shocks.

Procedure

  1. Locate terminals 7(-) and 8(+) on voltage regulator printed circuit board (VR21).
  2. Use a six volt dry cell battery with two clip leads and a 12 amp 300 volt diode as shown in Figure 6.
  3. If a six volt battery is not available, a 12 volt automotive battery can be used by adding a 20-ohm resistor in series.
  4. If using a 24 volt automotive battery, add a 40-ohm resistor in series.
  5. Start engine.
  6. Touch positive (+) battery lead to the +8 terminal.
  7. Touch negative (-) lead to -7 terminal just long enough until voltage starts to build up or damage may occur to exciter-regulator system.

Tools required

  • 6-volt dry cell battery
  • Two clip leads
  • 12 amp 300 volt diode

Specs & torque values

  • 6-volt battery or 12-volt with 20-ohm resistor or 24-volt with 40-ohm resistor
  • Voltage regulator terminals -7 and +8

Source: manual:900-0184 Onan YD Generators & Controls Service manual (11-1983)L.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.