Troubleshooting
42
MGG155/210 Operating Manual
35319 C
Table 6 - Digital Controller Troubleshooting Guide
Problem
Possible Cause
Solution
Controller Does Not
Power Up Even With
Correct DC Power
Applied
Wiring mistake.
Overload condition.
Check that there are no wiring errors/short circuits connected to
the controller.
Check breaker on the control panel.
Check fuses on control panel.
LCD Display Cannot Be
Viewed
Improper supply voltage.
Improper contrast adjust-
ment.
Check DC supply voltage at terminals B+ and B- (10-30VDC).
Adjust LCD contrast for best display.
Controller Cannot Be
“Reset"
Engine not stopped.
Controller not in OFF
mode.
Verify the engine is at a complete stop before trying to reset.
Set the controller to OFF before trying to reset.
No “RUN" Output Signal
“Shutdown Faults" not
reset.
Engine speed not detected
at cranking.
All shutdown faults must be reset (red shutdown LED must be
OFF).
Engine speed signal must be detected (speed signal green LED
on) during cranking if the “run-output fail safe" feature is enabled.
Verify correct magnetic pickup signal at cranking (2.0VAC min.
during cranking).
Overspeed Shutdown
Occurs At Normal
Speed
Controller programmed
values are wrong or con-
troller has failed.
Verify the controller programmed values are correct for the num-
ber of flywheel teeth, nominal RPM, and overspeed set point per-
centage. Replace controller if failed.
Voltage Or Current
Metering Is Incorrect
Controller programmed
values are wrong.
Ground is missing.
Voltage sensing wiring
mistake.
Verify the controller programmed values are correct for the volt-
age sensing PT ratio and/or current sensing CT ratio.
Verify that the battery supply DC negative conductor is properly
grounded to the engine block (i.e. to a common ground point).
Verify the voltage sensing wiring connection to the controller
matches power distribution type.
NOTE: Standard direct voltage connection requires that the gen-
erator neutral is solidly grounded.
Engine Temperature Or
Oil Pressure Display Is
Incorrect
Failed engine sensor.
Ground is missing.
Verify engine sensors.
NOTE: Engine sensors must be factory supplied only.
Verify that the battery supply DC negative conductor is properly
grounded to the engine block (i.e. to a common ground point).
Engine Alarms Are On
For High Engine Tem-
perature Or Low Oil
Pressure When Engine
Is Operating Properly
Wrong temp or pressure
calibration.
Verify the engine mounted senders have correct resistance values
for corresponding input temperature or pressure.
Verify calibration.
Keypad Buttons
(Switches) Do Not
Operate
Keypad not connected to
controller.
Verify the interconnecting ribbon cable between the Lexan™ face-
plate and main printed circuit board is correctly connected.
Replace controller if failed.
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