70 CHAPTER 6: MAINTAINING HARDWARE6 Connect the power cords to separate AC power sources on separate power gridsor to a UPS/backup power system.WARNING: Do not power on the switch until you reconnect all the components.Replacing a PowerSupplyTo replace a power supply, you need:■ An antistatic wrist strap■ A screwdriverWARNING: When installing or replacing the power supply when the power is on,do not touch any naked wire, terminal, or any other part of the product labeledDangerous Voltage. Always wear the antistatic wrist strap when replacing thesupply.Use the following steps to replace a power supply:1 Loosen the captive screws in the supply that you want to replace.2 Support the power supply you are removing with one hand and gently pull thehandle with the other hand until it slides out of the slot.3 If you are not going to install another power supply in this slot, install a blankingplate on the chassis for dust-proofing and heat dissipation.4 Remove the new power supply from the package and check the input mode.5 Support the power supply in one hand and hold the handle with another hand.Align the supply with the guides in the chassis and slide the supply gently into theslot.CAUTION: As you are inserting the power supply, if the pin terminal springs up,the pin cannot be seated into the hole and the system will sound an alarm. If thepower supply has not been inserted properly, you should slide it out and insert itagain to avoid breaking or cracking the power terminals.6 Fasten the captive screws.CAUTION: If the captive screws cannot be fastened, the power supply may nothave been properly seated. Remove and replace the supply.Over time, the filter on the power supply accumulates dust, which interferes withthe heat dissipation of the chassis. It is important to periodically clean the filter asdescribed below:1 Remove the gauze filter by gently pulling it from the front of the power supply.2 Take the filter to a fresh water supply and clean it.3 Leave the filter to dry. Do not use heat to dry the filter as this may cause it todistort.4 When the filter is completely dry, gently push it back into the front of the powermodule.CAUTION: Do not clean the filter while it is in position at the front of the powersupply. Attempts to do so could result in damage to the equipment or severeelectrical shock.