Brick PSP 1000 Repair

A few years ago I installed some CFW onto my PSP using a pandora battery I made and a memory stick I also made. I followed a guide online and everything worked well. I Accidentally deleted the firmware and it bricked my PSP. When I turn it on i get the green power light but a black screen. I am turning it on without battery in it and only using AC adaptor because I do not have a replacement battery. Do you know how I can fix my problem,?