- This indicates that the control board at the bottom and the drive board at the top are not communicating properly. This communication occurs over the GS cable with voltage being supplied from the control board.
- Check that there is 24V between GS and COM.
- If there is not, try disconnecting the GS cable and measuring between the GS and COM terminals:
- If you get 24V with the GS cable disconnected, there is a short somewhere up the line.
- If you do not get 24V with the GS cable disconnected, the control board is either not powered, or is possibly shorted or damaged.
- If the latter is the case, please contact technical support for further assistance.