Replaced Motherboard but still no power, help!

got the macbook, they said the screen didnt work and hinges were broken. i replaced the LCD cable and hinges then tried to boot it up and nothing. so i replaced the motherboard and it still will not boot. it will chage the battery however.

heres what i have done so far:

- checked dc jack, reading 14.5 V

- checked power pads, reads 3.3 to ground and 3.3 when bridged

- unhooked everything except power adapter, no boot

- unhooked everything except for charged battery, no boot

i tried all the above trying to boot with both the keyboard and powerpads with no luck. also tried the above with and without memory.

any ideas?

thanks,

justin