RX2702V's Tail gyro needs a digital servo @ 333hz, thats what the stock 2610H is. DS520 works good but is super sensitive which means the heli has to run tru with no vibes or else a wag will show up. The better option is Futaba S9257 mini out of the 2 but its 60 bux. I dont mess around with cheap servos anymore, not worth the trouble. Sometimes you get lucky sometimes you dont, but with servos you mostly get what you pay for just like anything else in this hobby. Usually its either really cheap or really expensive and no in betweens. But times are changing.
Although I am hearing really good things abou the hobby partz Solar servos and they seem reasonable, center well etc. Fusonic, Power HD are hit or miss. Wow Hobbies....no comment.
Another thing that kills this heli is if you keep it on the bench too long running test and dialing it in, seems to overwork the servos and stress electronics....Bind and Fly. It seems the guys who fly them more than work on them have less problems, or maybe they dont notice the problems and just get it in