power pack/ help please

Hi Guys
Can someone please tell me how do I test the power unit in my Acer Aspire Z5761 all in one pc as I still have the back off the PC and when I power the PC up it kind of runs for a few seconds can see blue lights going but nothing what so ever on front of screen , after a few seconds a click sound can be heard and then lights go out . I notice the fans are still running and I could see the fan in the power unit also still running but screen still doesn't light up. I have read somewhere that this was a fault with this model unit but at the moment know one has worked out what it is that is causing it and how to fix it . As I am limited with funds and can't afford to take it to a repair shop , I would if I could try and fix this problem myself with the help of the nice people in here . Again thank-you for all your help .

 

that psu uses standard connections, so any modern power supply testers would do the job. They are relatively cheap and easy to use.

 

CleaverX
Thank-you for that will check it out