Maintenance and Troubleshooting
21
Problem Observed
Possible Cause
Solution
LED brightness is wrong—entire
display is too bright or too dim.
Light sensor assembly is
obstructed.
Clear obstruction.
One or more wires or terminals
in the light/temp control
cable are misplaced, open or
shorted to other wires or the
frame in display, Vanguard
®
Field Controller, or control
cable from display to
Vanguard
®
Field Controller.
Repair as needed.
Light sensor is not configured
correctly.
Correct the settings. Refer to
the controller manual.
Light sensor printed circuit
board (PCB) is bad.
Replace light sensor.
Vanguard
®
Field Controller is
bad.
Refer to the controller manual.
Pixel test shows all pixels on all
display lines as bad. Display
lines play messages correctly.
Fiber or RS422 display output
RX not terminated properly
(fiber or copper option).
Re-terminate display output RX
connections (fiber or copper
option).
Vanguard
®
Field Controller is
bad.
Refer to the controller manual.
One or more internal
temperature sensors not
reading.
Signal or power wiring is bad.
One or more wires or terminals
are misplaced, or are open or
shorted to wires or the frame at
one of the temperature sensors
or the VCB.
Repair wiring as needed.
One or both of the
temperature sensors is bad.
Remove connectors at the
temperature sensor to test one
sensor at a time. Replace any
bad sensors.
VCB is bad.
Replace VCB.
Temperature sensor is not
configured correctly.
Correct the settings. Refer to
the controller manual.
One power supply indicates
“bad” from the operator
software or the Vanguard
®
Field Controller. All others
indicate OK.
One isolation board is bad.
Replace isolation board.
Bad power supply.
Replace power supply.
Wiring for power supply in VCB
is bad.
Repair as needed.
