dunno what IC this one is for but if it is indeed bad you have few solutions:
1/ sell it for cheap and buy another one
2/ send it to ken at www.irepairsega.com but you have to pay for shipping and repair charge (75$ /hour IIRC) I think it is worth for a pricy item. Ken is the man! he has always been of good help! super service!
well i'd say it depens on how cheap you can get a spare N2 mobo! ( and postal costs in Italy obviously :p )
Then what footix said is correct. The Naomi has been damaged. Although you may find ic117 on the Naomi board, I doubt that you can repair this yourself. The electronics on the board are very small and requires alot of skill to remove and replace. But, since it is already broken, you can try.