Had problems with my Android box at the weekend, I would turn it on and get the `Android' logo on the screen, but it wouldn't get as far as the main menu.
I noticed than when I plugged the power supply into the back, the power light would be bright for a few milliseconds, then fade slightly and then flicker occasionally.
Checked the PS output and it measured 5.4v but I thought it might be dropping off under load.
I purchased a universal one with different connectors, and selectable voltage output, thinking that it could be used as a backup for any others that might fail if it didn't sort the problem.
It did, Android box now working perfectly again, for the princely sum of €12