PSP power light comes on and goes out immediately

[Jaffa]

As the title says, the light comes on for a nano second and goes off, with power adapter in the orange light comes on but it wont power up.

bit of back info.

I have only got this refurbished from Sony as mine had a card reader problem, I put custom firmware on it and was playing Tiger 08 and it just went off.

I have read around google and someone said if you put usb lead in and try it, that it might work as there may be a loose connection, I did that and immediately it worked and thought thats o.k, but it wont go on again now and I cant send it back as it has custom firmware on it.

It wont power up at all, not in rocovery or anything, I have tried jiggling it about but no joy. I will try again tomorrow and if I get it I am putting offical back on and sending it back. Just thought you guys may have a idea or two before that.

Thanks in advance