For those wanting to replace ReadyNAS 600/X6 for out-of-warranty self service or other reasons, this FAQ will give you the information necessary to find a replacement fan that meets the specifications required from the fan driver circuitry on the main board. We believe current our fan selection is optimal for operating temperature and noise. Therefore we do not recommend replacing the fan unless it is necessary. FAN must be selected with following considerations. First two criteria must be satisfied before third one. • Do not stress FAN control circuitry. • Provide enough air flow and pressure at the heavy load condition. • Maintain as lower noise as possible. Before proceed, please understand our warranty policy which will become invalid after replacing components (except SODIMM and hard disks). Please take this into serious consideration before proceeding. ReadyNAS 600/X6 Rev.B has two FAN connectors labeled as “FAN1” and “FAN2”. The FAN1 connector has ability to control FAN speed, w