Thanks guys for your help

@Veti I've removed all wiring already and going through it with a fine tooth comb. I'll order some fuses now.

@Veti excellent, thank you. That seems to be the problem. I don't have any 7.5a fuses laying around but do have a 15a one. Would I be able to use one of those to see if I can get it up and running whilst I order some 7.5a ones??

@dc42 I do have one but, not very good at using it. What settings would I need the multimeter to be put on to check and what would I be looking for??

@dc42 No there doesn't seem to be any damage to the u3 chip or anything around it.

@dc42 is there anything else I can try??

@dc42 thanks for helping me. I just checked and the 5v internal enable jumper is installed on the board.

Hi
I'm having issues powering up my board. When I power it via USB it powers up fine but, when I power up via a psu it doesn't boot up and just the vin light is on. Is there something I should be checking??

@dc42 Hi. I believe I may have a similar problem and would just like clarification.
When I power my board through either a 24/12v psu the blue vin comes on and when powered via USB both +5v and +3.3v lights come on. I also have the INT_5V_EN jumper in as well. Would mine be the same problem??