# Servo Troubleshooting Help Please



## spideranne (Jul 17, 2006)

Ok, so I'll preface this by saying complete newbie at servos. I've attempted to search for an answer and I end up on sites that I only understand every 4th word, so before my brain explodes I thought I'd ask you guys. 

I'm building a 3 axis skull. I bought the twisty kit that included the servos, which are TowerPro SG 5010. I have a Pololu Mini Maestro 12 controller and their control center software. So, 3 out of 4 servos work fine. I plug them into the controller and move the slider bar on the software back and forth and they move accordingly. The servo for my rotate did not. It made a slight noise when plugged into the controller, but does nothing after that no matter what settings I used on the controller, and it started getting very hot. I thought it might be binding on something so I took it off the skull plate and tried it on its own. What I've determined it does is when I plug it into the controller it rotates all the way counterclockwise and holds there, which I'm guessing is why it gets so hot. It doesn't matter which of the 12 ports I plug it into or what the settings are on the controller, it always does the same thing. That's as far as I've gotten and am not sure what I should try next. 

Any help would be appreciated. Thx.


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## Hippofeet (Nov 26, 2012)

Do the other servo's do the same when connected to the port? I assume not, since you say the others work fine, but do any of the others work for rotation? Does the servo you want to use for rotation function when connected in place of one of the other servos? Is there an adjustment for centering rotation, or does the servo (or at least the others) self center when connected? Have you tried opening the servo, and seeing if all three wires are still connected? If you do, just pay attention and slowly open it, and look at the gears as you do. If one falls out, I can put up a vid of taking one apart and putting it back together. To me, it sounds like the servo is missing a return telling the controller where it is, or the controller itself is bad. Do you have more servos? I would try one in its place if so, if you haven't already done that. It is strange that it is getting hot. If it is not moving anything, and has no rod connected to the output shaft on the servo, and it is receiving a signal (voltage) telling it to turn counterclockwise, it should just continue to turn, not turn so far and stop. I don't know what would make it go so far and stop, and still be trying to turn and heating up, as far as a signal from the controller. It's just a motor, with some gearing inside the case, with a constant signal, it should just turn and not stop. Every port. Huh.

I'm guessing, bad servo. Bad connection on the card from a wire, or something. I would order a new one, or something that looked similar from allelectronics, or someplace, and then open that sucker up and see whats what.

Thats all I got. Questions, and a pretty dicey guess.


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## HomeyDaClown (Oct 3, 2009)

That is very unusual since we test every servo. But it does seem from what you've done that the servo is bad. I would guess that the internal position sensor pot is either bad or has lubricant on it (a bad thing for a servo). PM me with the details and we will get you a new one out right away.


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## spideranne (Jul 17, 2006)

Yes it's just the one servo, other servos in the same port work fine, and I guess I should mention that these only go 180 degrees so when it goes counterclockwise it eventually hits its stopping point and then won't move. I haven't attempted to open it up as that is way past my skill set. To be honest I'm running under the assumption that I must be doing something wrong vs. the servo being off so the fact that it could just be the servo actually makes me feel better.

Homey - Thank you, I'll PM you.


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## halstaff (Nov 18, 2009)

HomeyDaClown said:


> That is very unusual since we test every servo. But it does seem from what you've done that the servo is bad. I would guess that the internal position sensor pot is either bad or has lubricant on it (a bad thing for a servo). PM me with the details and we will get you a new one out right away.


Now that's customer service!


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## Zombie-F (Apr 12, 2004)

Sounds like a bad servo. It must be hitting it's stop point and is just trying to go further, which is why it's heating up.


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## Wildcat (Nov 3, 2007)

Agreed with halstaff, that is excellent customer service.


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## Hippofeet (Nov 26, 2012)

And I learned something. How do I like a post?


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## spideranne (Jul 17, 2006)

Yep, Homey's got me covered, couldn't ask for better customer service.

And now I know that that was not normal behavior for a servo. I think my technology IQ goes up a point. :googly:


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## mkozik1 (Sep 6, 2010)

You ROCK Homey!! I'm buying EVERYTHING from you from now on


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