Dot matrix display troubleshooting

Several conditions can cause a blank display:

1. Loss of power: For a discrete-input display, verify that 110 VAC is present on the two outside terminals of the JP1 connector. For a MicroComm-input display, verify that approximately +24 VDC is present between terminals 1 and 2 on the J2 connector.
2. Incorrect input signal: If the display has power, verify that only the current floor signal is active.
3. Incorrect programming: Contact CE Electronics technical support with the serial number from the white label, typically found on the side of the transformer, so support can determine how the display was programmed.

Check the direction signals and display programming:

1. Make sure the up and down direction signals have the correct voltage connected to the WHT/RED and ORG/RED wires in the wiring harness.
2. The up and down arrows must be programmed into the display along with the floors. Contact CE Electronics technical support with the serial number from the white label, typically found on the side of the transformer, so support can determine whether the arrows were included in the program.

This normally means the display is receiving no floor signals, or the signals have the wrong voltage or polarity. Some older units show CE instead of D.

For DHXXX or DVXXX displays, resistors R1 through R8 determine the expected signal voltage:

DH and DV displays are polarity-sensitive. Ensure that the BLU/RED and RED/GRN wires are connected to the correct return for the floor signals. If the signal voltage is DC and the board has the wrong polarity, contact CE sales for a board configured for the correct polarity.