I'm trying to test a PSU before going to all the hassle of connecting it up to everything (I've arthritic hands that make connecting things very painful so I prefer to only have to do it once!), but as I've tried 2 now that "appear" to not work i.e. the fan doesn't turn, I'm wondering if perhaps they do have to be connected to something perhaps on the board to get them going and if so, what's the least required?? Have I killed them not having them connected first?

ATX PSUs are switched via the motherboard (and therefore the power switch on the PC case). To get one to work without connecting it, you would need to short across the relevant pins on the motherboard connector.

Doing that however does risk some damage to the PSU and more importantly to you. So I can't in all conscience recommend it. I'd really rather you plugged them into the motherboard. You don't need to connect any of the drives if you just want to test the PSU powers up. Although a PSU can work in the sense that it powers up and still not be right because it has to be able to supply 3 voltages under load and obviously in the above scenario, it isn't.

If you've just been plugging them in without shorting them, then no they won't work. But equally you won't have damaged them.

THanks SO much = you've more than answered my query on this with all the info I needed - so at least now I can rest content that I'll just have to bite the bullet and hurt my hands once more on this task, but hopefully it'll work fine and that will be it done with. Good to know all that info on it tho save me making any errors at some future point perhaps.

Thanks again.
(Don't feel quite so daft now LOL!)