Q: Why does my display show “2V”? (Some older displays may show “OK” instead.)

A: This indicates that the display is either not receiving any data from the driver, or something is keeping the data from being recognized.

1. Check the voltage between terminals 1 and 3 (or the BLK wire and WHT wire if your display has a pigtail) with your meter set to DC volts.  Put your black meter lead to terminal 1 (or BLK wire) and your red meter lead to terminal 3 (or WHT wire).  You should see voltage that fluctuates between +1.4vdc and +2.2vdc.  If the voltage is correct, but is negative, or if the voltage fluctuates between +3vdc and +4vdc, then swap the wires between terminals 1 and 3 (or BLK and WHT).
2. If the voltage between terminals 1 and 3 is less than +1vdc, then check the plug-in data protection resistor next to the MICRO COMM® output connector on the driver (R17 on the SMCDU and R46 on the MCCA).  Unplug the output connector, remove the resistor, and measure its value with your meter on Ohms.  It should read 51Ω ±5Ω, if it doesn’t, then it needs to be replaced.  If it reads correctly, then your driver needs to be repaired or replaced.
3. If the voltage between terminals 1 and 3 is around +8vdc, then your driver needs to be repaired or replaced.
4. If the voltage between terminals 1 and 3 is correct, then your display probably needs repaired or replaced.