Baldor GLC125, GLC35, GLC80, GLC50 manual Troubleshooting Guide Digital Controller Only

Table 5-2 Troubleshooting Guide (Digital Controller Only)

Problem	Possible Cause	Remedy
Controller does not power up even with	Wiring Mistake	Check that there are no wiring errors/short circuits connected to the
correct DC power applied		controller.
	Overload Condition	The MEC 20 contains an electronic fuse that trips when an overload
		condition exists and does not reset until the supply voltage is
		removed and reapplied after the overload condition is corrected.
LCD Display cannot be viewed	Microprocessor failure	Check that the controller's microprocessor is running by observing a
		red flashing •watchdog" LED on the rear of the PCB. Replace
		controller if failed.
	Improper Supply Voltage	Check DC supply voltage at terminals B+ & B- (10-30VDC).
	Improper contrast adjustment	Adjust LCD contrast potentiometer (R115) on rear of PCB for best
		display.
Controller cannot be •Reset"	Engine not stopped	Verify the engine is at a complete stop before trying to reset.
	Controller not in OFF mode	Set the controller to the OFF mode before trying to reset.
No •RUN" output signal	•Shutdown Faults" not reset	All shutdown faults must be reset (red shutdown LED must be off).
	Engine speed not detected at cranking	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).
	Run Contact not closing (terminals #18 & Check that the RUN output LED (on the rear of the PCB) is on.
	#19)	If yes, verify relay contact operation on terminals #18 & #19.
		Replace controller if failed.

Overspeed shutdown occurs at normal speed

Controller programmed values are wrong or controller has failed.

Verify the controller programmed values are correct for the number of flywheel teeth, nominal RPM, and overspeed setpoint percentage. Replace controller if failed.

Voltage or current metering is incorrect	Controller programmed values are wrong	Verify the controller programmed values are correct for the voltage
		sensing PT ratio and/or current sensing CT ratio.
	Ground is missing	Verify that the battery supply DC negative conductor is properly
		grounded to the engine block (i.e. to a common ground point).
	Analog input needs to be calibrated	Verify that the controller's analog input is properly calibrated.
	Voltage sensing wiring mistake	Verify the voltage sensing wiring connection to the MEC 20 matches
		power distribution type.
		Note: standard direct voltage connection requires that the
		generators neutral is solidly grounded.
Engine temperature or oil pressure	Analog input needs to be calibrated	Verify that the controller's analog input is properly calibrated.
display is incorrect	Failed engine sensor	Verify engine sensors.
		Note: engine sensors must be factory supplied units only.
	Ground is missing	Verify that the battery supply DC negative conductor is properly
		grounded to the engine block (i.e. to a common ground point).

Engine temperature or oil pressure displays 9999

OR

Engine alarms are ON for high engine temperature or low oil pressure when engine is operating properly

Sending unit is disconnected (open	Verify the sending units wiring to controller terminals #37 & #38 (i.e.
circuit)	wiring is not open or shorted).
Defective sending unit	Verify the engine mounted senders have correct resistance values
	for corresponding input temperature or pressure.
Wrong Temp or pressure calibration	Verify calibration.

Keypad Buttons (switches) do not	Keypad not connected to controller	Verify the interconnecting ribbon cable between the lexan faceplate
operate.		and main printed circuit board is correctly connected.
		Replace controller if failed.

MN2408 Troubleshooting and Maintenance 5-3