power suply on dream 800

[porter1]

got a universal power supply from maplins,the tip has to be connected either by centre positive polarity or centre negative polarity,anyone know what way it should be to popwer the 800,most probably a totally daft question but not sure,cheers
found out its positive polarity if anyone needs to know

[sproot]

why not try negative first ,that way no problems if wrong.?
oops its +

[porter1]

working now m8,new image,just trying to get ip etc ,cheers