#1. "RE: D90 and a bad GPS port" In response to Reply # 0
I also have a D90 with a faulty GPS port. And, like you searched the net about this failure and agree it seems to be a common problem. I contacted Nikon support as well as the head of customer service. Nikon denies a problem, hiding behind the belief that since Nikon has not published a service bulletin, therefore no common problem exists. Needless to say, I found their response to be shallow. It's like an ostrich putting its head in the sand and pretending danger is not present.
As I understand it, the main circuit board contains the GPS port as an "appendage" and needs to be replaced. The estimates from a well regarded Nikon authorized repair shop and local repair shops are all in the range of $275-$300.
Perhaps Nikon needs to hear from all owners of Nikon cameras that have faulty GPS ports.
#3. "RE: D90 and a bad GPS port" In response to Reply # 2
I contacted David Dentry. I found his name mentioned on the Nikonians forum when searching for GPS port problems. In my problem summary to his attention, I did include quite a few links to support that the problem originates from faulty design, has been experienced by others, and the problem affects other Nikon camera models in addition to the D90.
Mr. Dentry's response was very disappointing. Will you please let me know if you have better luck?