User replacement of the Power Supply is a simple and easy task which requires only a #2 Phillips (medium size cross-point)screwdriver and a little patience... , as follows:  

1. Ensure that the external power cord is disconnected.

 2. The left side panel is held in place with two Phillips head screws at the rear.  Remove these two screws and slide the panel back and remove.  This exposes the Power Supply and its wiring.   Simply reach in and disconnect the two, 4 pin Molex connectors from each of the two Backplane / Circuit Boards.  You don’t need to be concerned about which connector goes where because they are all the same.  The only difference is the length of the cable.

 3. In some older units the fan may be connected to a 2 pin pigtail from one of the power supply connectors, if so, unplug the Fan connector from this pigtail and plug it into the 2 pin connector on the back side of one of the Backplanes.  See the partial view below:

 4. There is also a cable leading to the Power Switch in the Front Panel.  To get to this Power Switch the Plastic Front Panel must be removed.  The Front Panel is held in place with 3 small plastic tabs on each side which protrude thru rectangular holes in the metal frame behind the plastic Front Panel.  This procedure must be performed GENTLY so as not to break the tabs.  On the Left side of the unit (the side that is open) there is an open slot behind the front panel.  Insert your finger in this slot, about 1.5 inches from the top and locate the plastic tab from the Front Panel that protrudes thru the square hole.  Squeeze this tab slightly and very gently pull the Plastic Front Panel forward (about an 1/8 inch) away from the unit.  Repeat this step for the tab at the center and again for the tab about 1.5 inches from the bottom.  Once all three tabs on the left side are released, the left side of the Front Panel will hinge out.  Now,  Very Very gently, wiggly the Front Panel a little to free the right side tabs and the front Panel should come free.

 5. With the Front Plastic Panel off, remove (and save) the two screws that hold the Power Switch in place.  With the Power Switch free and all 4 of the Power Connectors disconnected from the Backplanes you may now remove the 4 screws holding the Power Supply in place and remove the Power Supply and its wiring from the unit.

6. Install the Replacement Power Supply and secure it with the four (4)screws.  Mount the Power Switch behind the Front Panel and secure it with the two 3 mm screws.  The silver push button on the old power switch will easily pull straight off.  Push this silver button on to the new power switch.

Re-mount the Front Plastic Panel by aligning the 6 plastic tabs in the rectangular  holes and press the panel straight on.  Each of the 3 small plastic tabs on each side which protrude thru rectangular holes in the metal frame behind the plastic Front Panel  should click and secure the Front Panel in place.  Now plug-in all four of the 4 pin Power Cables into the Backplanes.  These cables are all the same except that they are different lengths, so if all four cable will reach, it’s OK to connect.

7. Now you may reinstall the side panel, replace the two screws and you should be ready to operate.  Now, that was not difficult, was it?