DS520 servo problem

[helimadness]

Hi All.

So had another little crash yesterday and stripped the tail servo gears. Replaced with new gears but when I turn the heli on the tail goes hard one way bottoms out and keeps trying to drive against the stop. I have the tail rod off so the servo has full travel to its limit.

I have plugged an old one in that I replaced when I had an intermittent fault (could have been the servo or the 3gx replaced both at the time) and it works fine. Plug the one in I crashed with and replaced the gears and it just goes hard to the stop. I can drive it back with the rudder stick but when I let go just goes hard to the stop.

Any ideas? Did the servo get toasted as well?

Cheers

[milly0812]

You will need to mechanically setup the tail again and reset the limits by the sound of it ;-)

[helimadness]

Yeah that is what I was about to do but when I turned on it just went hard one way and jammed. I pulled apart again and compared to the other one. When I put back together It seemed ok. I think I must have messed or it was getting a messed up reading from the position sensor and wasn't finding the home place properly.

Cheers

[cjcj1949]

Perhaps you didn't have the pot turning from the gears when you put it back together. I've taken mine apart when I thought it was at fault and I think you have to have things lined up.

[helimadness]

The servo arm was moving, went hard to the stop. Ended up munching the new gears a bit as well. Had some spares luckily Not sure why but pulled apart took the gears out and powered up. Then manually turned the pot till it zeroed itself. Put all back together and was happy. Maybe went out side the limit on the put or the Vbar software and lost itself. Maybe good to check when you put them back together you have the pot zeroed before putting the gears back in. Easy to do.

Cheers

[cjcj1949]

A current limited power supply is useful for checking things out. I have a Maplin one that cost about £60 which is in use all the time. You can set the current limit to under an amp for setting up purposes. You could also use some old AAA batteries. MKS recommend a separate power supply (regulator) for each servo to prevent damage. I can find the links if you want. I find the power supply as useful as a meter. The MKS approach is a good cheap solution to digital servo burnout and allows you to run the rx at a higher voltage like a 2S lipo. The telemetry then tells you the battery voltage from the rx.