Lenovo ThinkSystem D4390 Hardware Installation And Maintenance Manual

68WARNING:Always comply with all electrostatic and thermal guidelines to prevent bodily injury and ensure a properlyfunctioning system when performing hot-plug operations.1) Locate the faulty PSU or the faulty fan module. Check the status of LEDs. See section 3.2.2 or 3.3.2 .● If the AC power LED is not on, check both sides of the power cord are plugged into the PSU and the powersource.o Connect another device to the power source to verify if the power source is working.o Replace the power cord.o Connect the cable to a different power source.o If the DC power LED is not lit, verify that the PSU is inserted properly. If the PSU is inserted properly,see step 2.● If fan fault LED is on, reseat the fan module. See section 3.3.3 .CAUTION:Power supply unit and cooling fan modules are hot-swappable. A single power supply unit or cooling fan modulecan be removed from a powered-on enclosure for a maximum period of 10 minutes. The minimum number ofPSUs to run the enclosure is two.2) Reseat the power supply by removing and reinstalling it. See section 3.2.4 .NOTE:After installing PSUs, allow several seconds for the enclosure to recognize the PSUs and to determine if it isworking properly.6.5 Troubleshooting Enclosure cooling ProblemsCAUTION: Many repairs may only be done by a certified service technician. You should only performtroubleshooting and simple repairs as authorized in your product documentation, or as directed by the online ortelephone service and support team. Damage due to servicing that is not authorized by Lenovo is not covered bythe warranty. Read and follow the safety instructions that came with the product.