28 Owner’s Manual
Wanco® Metro™ Message Sign
High display-cabinet temperature
The temperature inside the display cabinet may be significantly higher than the
ambient temperature, due to solar gain. If the temperature (Ts) is too high, the message
sign display shuts down and the display is blank.
A temperature alarm can also occur if a temperature sensor, the sensor circuit board, or
wiring to the sensor is faulty, even if the display cabinet temperature is not too high.
To troubleshoot high display-cabinet temperature:
1. Follow the safety requirements in Section 2, page 3.
2. Open the display cabinet door.
3. Locate the sensor circuit board, which is also the photocell board (see Figure 5-2).
4. Check wiring connectors to the sensor circuit board, ensuring they are proper and
secure.
5. Check wiring and wiring connectors for damage, and repair or replace if necessary.
6. If wiring connections are secure and wiring is undamaged, the sensor circuit board may
be loose or damaged. Inspect the sensor board and replace it if necessary (see
Section 5.2.7).
High computer-box temperature
If the temperature inside the computer box (Tc) is high, the power board or a
component on the board may have failed. In this case, the power board should be
replaced. Contact the factory for a replacement power board (see Section 1.4, “Where
to obtain service,” page 2).
The power board replacement procedure should be performed by an authorized
Wanco service technician.
5.2.7 Photocell alarm
A photocell alarm results when one or more photocell inputs are out of range. The
message sign is equipped with two photocells, which are used for controlling the
brightness of the display.
■ If the display appears to be abnormally dim, one or both photocells may be blocked or
defective.
■ If the display appears to be abnormally bright, one or both photocells may have short-
circuited or become damaged.
If a photocell alarm occurs:
1. Follow the safety requirements in Section 2, page 3.
2. Follow the procedures in Section 5.3, page 30, to access and inspect the main terminal
strip inside the display cabinet.
3. Locate the photocells in the lower left corner of the display cabinet (see Figure 5-2).
To Next Page
Loading...