5dvd home theater system error F61?

Four years ago, just after 2days of manufacturer warranty it happen, i have error F61. since that time unit stayed in the box. some one told me some one help me out at this site. When you turn the power on it show F61 and shut of quickly. And If you put 12v to fan out of unit it works like new and it's clean no dust or any thing on it . From power supply to the board which has fan, comes 11.89v. which is good enough for fan and the board. My unit is not working. Please help me out. Thanks.