After screwing up my friend's first mobo (a 1.6a) I ordered a new mobo/HDD from eBay to fix the problem. It turned out to be a 1.6b. I put the new motherboard in but it will not boot at all! the power LED doesn't come on at all! I out the old one back in and at least the LED flashed.... What could my probem be? Is the new mobo dead? Thanks.

Am I going to have to do the transistor repair found here?:
http://www.llamma.com/xbox/Repairs/1.6_Xbox_no_power.htm

Yes, you have to replace that transistor, it is a common problem with 1.6's.

Crap....

thanks for the help.

just take it off the old 1.6, lol

yeah, lol, that's what I was thinking of doing. I allready pulled it off the old one, but I haven't put it on the new one yet. because I might be able to return it without the possibility of screwing up the new one even more.

Well, I said screw the eBay guy and I took the piece from my old motherboard and put it on the new one and it started up on the first try!