Is my airport or motherboard damaged??

I have an iBook G3 and the wireless works only if I am close to the network router... I switched airport cards and realized that that was not the source of my problem. All other iBooks work beautifully except mine. My brother checked it out too and said it's my motherboard... anybody have a clue of what the dilemma might be?

Make sure that the little antenna cable is plugged in correctly on the airport card. You can probably try to clean the connector of the cable itself. Maybe its dirty?