PSU switch question

[thered]

Got a new PSU for my old dm7025

but like a ding bat i never checked the wires before removing the old one the problem is simple but its 50/50 i will get it wrong

i have a blue and brown wire from PSU that needs to go to the on/off button

problem is i dont know which of the 2 is the live terminal

the switch has 2 pin with 1a above 1 pin and 1 over the other

there is a blanked part with no pin that says 1b

would i be right in thinking 1a would be the live??

dont want to ***** it up

thanks

[Fergal]

Found this if its any use.

[thered]

Thanks lads i did think that that may have been the case jok but i want sure and i didnt want to **** out up but i will put it in as shows in the picture above cheers