hey if you find a good replacement board, lemme know.. i dont wanna spend the 45 bucks for a new 3-in-1, and i cant find cheaper.. mine does the same thing.. just opposite, i dont know why.. but same exact thing with me, one day it just bit it, tail rotor wont spin at all.. and i guess messing with it i contacted something or idk what, but my main rotor will spin full speed and wont slow down for nothin.. and i too still have control of all my servo's though

just a side note.. i actually DO know what i contacted on the e-board(on accident) that made the main motor spin at full rpm, i just dont know why.. but im probably gonna use the e-board and put it on a little home made balsa plane.. you can make a varible pitch prop out of a heli tail, use one servo to control that, the other 2 can be an elevator and rudder..
ok actually, i just came up with this idea as i was typing.. and im really excited to go try it!!

if you think thats not that bad of an idea i can put pics on here to show you what it was.. heck you could make the plane, and then sell it to pay for a new 3-in-1 ;D