I've got 9351s for my large scale planes and I have the same problems as others with the servo vibrating if you centre them too fast and it starts to oscillate around neutral.I've read the threads about other guys having the same problem and that they're not actually meant for planes.But I have 10 of them and don't intend to purchase another bunch of 9155 soon. Is there a fix for these either by software or adding a resistor?
I got these servos sometime back from someone in the US who was flying it in his plane.Some are brand new and the rest were hardly used. How do I tell if its been modified and what would be the cost for a fix?

Is it because the 9351 has a very tight deadband and metal gears have a slight slop compared to nylon gears that causes this to happen?

Thanks very much