Dell Inspiron 1545 not starting up

Hello, I have just brought a second hand Dell inspiron 1545 Laptop.

It worked fine, The only trouble was, that there was an issue with it only running on mains power and the battery was not charging.

I was told that the Charging jack board needed replacing ( a common problem with these models I understand)

I replaced the board and put everything back together only to find that it's now not working at all even on mains power.

Any ideas? before I have to strip the whole *** thing down again?

Thanks very much.