Log in to the LMT. Then choose Alarm Maintenance > Browse Alarm. If you find an alarm about the faulty board where the HDLC is configured, then you can infer that the board is faulty. You can also select the BSC Device Panel tab, and then check the colors of the GEHUB and GFGUB boards. If they are in red, then you can infer that the board where the HDLC is configured is faulty.