For my Hexapod project, I plan to use standard servos. As I don't want to spend too much money in this project, I ordered a TowerPro MG995 from ebay. But I got a clone! No bearings, and a huge dead band (~15°!).

I then ordered 4 TowerPro MG996R from HobbyKing, which sell original ones (I asked TowerPro first), to make some tests.

These servos are designed to go to the target position as fast as possible, and maintain it with big tork. But when I try to move them slowly, as I need to do to make my Hexapod walk, they have huge jerk

So, I was planning to make my own electronic, based on the dead OpenServo project. I removed the electronic of the MG995, to make some tests with an arduino. Doing this, I found that the electronic of that servo uses the Agamem AA51880 chip. But they don't use the values Agamem gives in the datasheet. Especially for the resistor controling the dead-band! I replaced their 2.2k with a 1k, and got some pretty good results, at least for this application.

Then, I opened the MG996R, and found that the controller chip reference is scratched . No way to hack them.

So, I plan to buy some original TowerPro MG996R, and replace the electronic. But the quetion is: where can I find these electronic based on AA51880? I'm sure there are some chineese company selling them, but I can't find one.

Another solution would be to buy the MG995 clones, and replace the resistors. And add bearings (they are available on internet). But again, how can I be sure to get the electronic based on the AA51880 chip?

Any idea?