Unplug, take the back off. look on the power supply circuit board for capacitors that are puffed up on the top. These should be replaced. there are about a half dozen of them & the cost at a local parts house is very reasonable. you just need to be able to solder(preferably with a temperature controlled iron & not a gun) without burning up the PCB.

HI,

instead get around testing our recommendation is to get the another power supply instead, that will be easy to just plug and play

here is your replacement
:
http://www.bostonrecycling.net/power-supply-board-main/1022-dynex-dx-l42-10a-power-supply-6kt0032012.html

and the shipping its FREE