Troubleshooting (Controller) - MULTIQUIP Power MQP20P Operation And Parts Manual

CauTiON
Before opening the enclosure to perform troubleshooting
or any service task, isolate the controller from any
possible source of power. Failure to do so may result in
serious personal injury or death due to electrical shock.
Symptom
Does not power up even
with correct DC power
applied
LCD is not operational
Controller cannot be
"reset"
No "RUN" output signal
Overspeed shutdown occurs
at normal speed
Voltage or current metering
is reading incorrectly
page 38 —MQp20p STaNDBY geNeRaTOR • OpeRaTiON aND paRTS MaNual — Rev. #1 (11/28/11)

trOubLEShOOtIng (COntrOLLEr)

Troubleshooting (MeC20 Controller)
possible problem
Wiring errors or short circuit?
Microprocessor defective?
Insufficient DC supply voltage?
Bad LCD resolution?
Controller not in OFF mode?
Engine is running?
Shutdown circuits reset?
No engine speed signal?
RUN output LED off?
Controller not correctly programmed?
Controller not correctly programmed?
Battery not properly grounded?
Analog input not properly calibrated?
Incorrect wiring?
Solution
Check wiring and repair. NOTE: The MEC 20 electronic
fuse triggers when there is an overload condition and does
not reset until the supply voltage is removed and overload
condition is corrected.
Check that the "watchdog" LED on the rear of the PCB is
flashing red meaning that the microprocessor is working. If
not, repair or replace microprocessor.
Check voltage at input terminals B+ and B- (10-30 VDC).
Adjust LCD contrast potentiometer (R115) on the rear of
PCB for good pixel resolution for the operating temperature
of the unit.
Check that the controller is set to the OFF mode before
resetting.
Check that the engine has come to a complete stop before
resetting.
Check that all shutdown circuits are 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 pick-up signal at cranking
(2.0 VAC min.)
Check that the RUN output LED (on the rear of the PCB) is
on. If yes, verify relay contact operation on terminals #18 and
#19.
Verify that the controller has been programmed with the correct
values for the number of flywheel teeth, nominal RPM, and
overspeed setpoint percentage.
Verify that the controller has been programmed with the correct
values for voltage 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 that the controller's analog input has been properly
calibrated.
Verify that the voltage sensing wiring connection to the
controller matches power distribution type (Note: standard
direct voltage connection requires that the generator's neutral
is solidly grounded).