Galaxy note dead; won't boot or charge

My cheapo charger went puff today while charging my Samsung Galaxy Note and then the Note died. It does not turn on. Plugging it on a brand charger won't display a charging icon.

I placed its m/board in another note and it won't power on. So the culprit is the m/board. I found one on ebay, but the seller says that when that m/board was in a phone, it could not get a signal. So the question is: Is the signal reception dependent on the m/board or just the 3g/gsm antena? Would it be safe to buy his m/board?