You better check it is safe. The communist Chinese flog a lot of dodgy equipment on eBay. Some of it is downright dangerous (I had seen examples of this). Some of it has safety approvals printed on the box or case, but it is fraudulent. Some don't even have safety approval labels at all. In Australia a lot of stuff is bought on eBay and illegally imported from third world countries like China.
I suggest before you do anything, open the power supply up and check for case earthing, bad solder joints, poor insulation, loose screws etc. Fix anything that looks dodgy.
Before you plug anything into the output, check the + and - are not reversed and is at the expected voltages.