In this video we will demonstrate how to replace the Power-Supply Unit or PSU on a ChengMing 3991 system. Before removing the PSU, read through the safety guidelines to protect your computer from potential damage and ensure your personal safety.
For more information about safety guidelines, see the ChengMing 3991 Service Manual at: Dell.com/support Before you begin, ensure that you turn off your computer and disconnect all attached peripherals. To begin with, loosen the two captive screws that secure the side cover to the computer.
Slide the side cover towards the back of the computer And lift the side cover away from the chassis. Next remove the fan assembly. Press the blue tabs on both the sides of the fan and slide to lift the fan to release it from the computer. Now let’s remove the PSU. Disconnect the power cables from the connector on the system board. And unroute them from the routing guides on the chassis.
Remove the three screws that secure the PSU to the chassis. Press the securing clip and slide the PSU away from the back of the chassis. Gently lift up the PSU off the chassis.
You have now successfully removed the PSU. Now, let’s see how to install the PSU. To begin, slide the PSU into the chassis until the securing tab snaps into place. Now, replace the three screws to secure the PSU to the chassis.
Route the power cable through the routing guides on the chassis and connect the power cables to their respective connectors on the system board.
Connect the 4-pin power cable to the system board. To install the fan assembly, turn the fan assembly over and press the release tab on the fan assembly until it clicks into place.
Align the side cover with the guidelines on the chassis. Slide the side cover towards the front of the system to install the side cover. Now replace the thumbscrews to secure the side cover to the system.
You have now successfully installed the PSU. You can now connect all the peripherals and turn on your computer. For more information, see the ChengMing 3991 Service Manual at: Dell.com/support.