Doran Warning Light Monitor - Blue Bird D3RE 2014 Driver's Handbook Manual

Doran Warning Light Monitor

The Doran Monitor™ is a current sensing device. If current is
flowing through one of the bus lamp circuits, the monitor
senses it and illuminates the corresponding monitor light
emitting diode (LED). When a lamp burns out, current flow
through the circuit stops and the corresponding LED on the
monitor does not illuminate, indicating the outside lamp is
not functioning. The Doran™ Monitor is located in the bulk-
head over the windshield and slightly to the left of the driver.
Warning lights are such an essential safety feature, it is
important to know when they are not working properly. This
is the function of the Doran monitor. Its display is a sche-
matic of the lights as they appear outside the bus. It continu-
ously monitors the current in each lamp. If current is flowing
through a particular bus lamp circuit (i.e., the light is on), the
monitor senses this and lights the corresponding monitor bulb. If the bus lamp burns
out, current ceases and the corresponding monitor bulb goes out, indicating a fault.
Once the defective lamp is replaced, and the warning lights are working normally
again, this also should be shown by the monitor.
The Doran monitor is a reliable, long-life device, but as with most electrical in-
struments, it can be overheated and damaged if an overload occurs in a bus light.
Such overloads can exist if a bus light circuit becomes shorted, forcing current
through a coil in the monitor that exceeds the coil's rated capacity. Short circuits
can occur if improper connections are made during installations, bus repairs, etc. If
the monitor has an optional thermistor overload protection, the tail light circuits are
overload-protected. (Thermistors are located on the bottom of the component side
of the printed circuit board.)
If the Doran monitor is not working properly, see Troubleshooting for units
equipped with incandescent lighting only. See Calibration for units equipped with
LED lighting.
Troubleshooting
The Doran Warning Light Monitor™ does not display any indicator LEDs:
1. An overload situation has created an open circuit. Check the system fuses.
2. An overload or physical damage has burned or broken a conductor on the
printed circuit board:
• Extra lights have been added to the circuit; i.e., trailer lights, etc.:
• Remove the extra lights from the circuit
• Replace the damaged printed circuit board
• Excessive vibration or abuse has resulted in a damaged monitor. Replace
the printed circuit board
CARE & MAINTENANCE
Calibration
Button
Green LED
Voltage Monitor
97