Hi MJ,
Silly question, but how do you know that you have power, do you hear or see something ?
Additionally, are you getting a good click when you depress the power button.
As a caveat, the builds on the 2 models may have subtle differences, which may explain why the phones behave so badly if you don't replace everything in exactly the right place and position.
I am not sure as I have a 32g 3gs, but recent experience tells me that you can bet the similar exteriors hide intentional, subtle interior build differences.
My advice is to try an 'exact' match if you can, as that gives you the best chance of troubleshooting in a 'methodical' way, so you don't have to back track which will mean you have to continue re-opening the top screen which will may cause you to damage yet another connector.
Good luck, and hope this helped.
GA
10-29-2013 06:58 PM