1-1MAJOR OPERATING CONTROLS AND THEIR FUNCTIONS Front ViewERRORHDD 1 HDD 2 HDD 3 HDD 4HDDPOWEROPERATEExtension UnitWJ-HDEq w e r tq Error indicator [ERROR]Lights when an error occurs. Refer to TROUBLESHOOT-ING for details.Red: System errorOrange: Thermal error or malfunction of the cooling fan.w HDD power indicator [HDD POWER]ON: Indicates that HDDs are powered.OFF: Indicates that the HDDs are not powered.Note: Do not move the unit until the motors of the HDDsstop completely. To stop the motors, turn off theHDD POWER switch behind the front cover. Movethe unit after confirming that the indicator has goneout.e Operate indicator [OPERATE]Lights green when turning on the power switch on therear panel.r HDD access indicators [HDD 1] [HDD 2] [HDD 3][HDD 4]Each indicator lights to indicate the status of the respec-tive HDD.Green: Indicates that the respective HDD is runningnormally.Red: Indicates that the respective HDD is the first faultydrive among the HDDs in the unit.Red blink: Indicates that the respective HDD is the sec-ond or subsequent faulty drive among the HDDs inthe unit.Orange-red alternate blink/Orange: Indicates that therespective drive is currently being recovered inRAID level 5 mode.These indicators normally indicate the status of therespective drive, but they work as a set when a systemerror occurs.ImportantWhen one of the indicators lights red, replace therespective HDD immediately. If two or more indicatorslight/blink red, it will be impossible to recover data.There may be cases where it is eventually impossible torecover data if two drives are coincidentally damaged orthe second drive fails during the data recovery process.t Front coverDetach the front cover when it is necessary to installHDDs or to operate the switches inside the unit.