Servos Align DS410M Melted (Please Help Diagnose)

[Bruno]

Align Trex 450 PRO. Align DS410M servo, Align BL 35X ESC. Align 450MX motor and AR7200BX reciever.

Fired up the receiver and she announced proper beeps ready for flight.

Put her on the ground, spooled her up to half throttle and she died.

Heard a single repetitive beep.

Upon inspection the align DS410M servo was smoking and the casing melted a bit.

I disconnected battery.

I connected battery again and the servo started smoking and casing melting instantly.

What happened?

 

[Derek]

Could there have been a short, in the servo? maybe something came loose inside the case and crossed something it didn't like. can you take the servo apart and check the guts?

 

[Lee]

Check the out put voltage of the servo wire from the ESC.
Maybe the BEC has died, and is sending the full 12V through to the servo?
Just a guess, but worth a check.

 

[Bruno]

Check the out put voltage of the servo wire from the ESC.
Maybe the BEC has died, and is sending the full 12V through to the servo?
Just a guess, but worth a check.

What should BEC servo output be?

 

[Derek]

I don't think that any of mine are more than 6.0v. So, if the BEC in your ESC failed, that could be straight 12v being sent out. I suppose it's possible.

 

[Slobberdog]

If the bec had gone and was flowing 12v that would have taken out the AR7200bx first and prob all the servos, as none of the components listed are rated above 7.4v are they

 

[Bruno]

If the bec had gone and was flowing 12v that would have taken out the AR7200bx first and prob all the servos, as none of the components listed are rated above 7.4v are they

Correct. The BX and other servos were not effected. I know this since when I reconnected the battery the BX functioned normal and the other servos did not indicate an immediate problem.

What about the single repeated beep I heard at the time of the malfunction? Any thoughts?

 

[Lee]

If the bec had gone and was flowing 12v that would have taken out the AR7200bx first and prob all the servos, as none of the components listed are rated above 7.4v are they

It was a long shot, but worth a look

It may just be bad luck. Servo decided to pack in.
Have you tried putting another servo into the RX port of the old one?
At the risk of frying another, it will tell you if it was an issue down the line, or it was just the servo.

 

[Bruno]

I connected a new pitch servo to the BX Aux 1 port and all seemed to initialize and function normally.

I hope this was simply a servo short.

I will disassemble the fried servo and post findings.

Any suggestions are appreciated.

I would hate to have this happen while in flight. It was concerning enough on the ground.

 

[murankar]

Has the servo been in any crashes? Are those plastic gears? Another long shot is the servo could have been jammed and it over heated. Again just a long shot.

Sent from my LG-E980 using Forum Runner

 

[Bruno]

Has the servo been in any crashes? Are those plastic gears? Another long shot is the servo could have been jammed and it over heated. Again just a long shot.

Sent from my LG-E980 using Forum Runner

Servos has been in crashes but flew many flights afterwards without a crash prior to this problem ....good point though. They are metal gears. Good ideas. Thanks.

I would rather it simply be the servo and no other electronics.

We will see what I may find when I get a chance to open up the damaged servo.

 

[Tony]

I wouldn't think it would be anything else other than a faulty servo. One way to check is to plug one of your other servos into that port and see if it gets hot. But to me, it sounds like the motor inside the servo gave up the ghost and shorted out. But built up enough carbon to stop the current flow the first time. The second time, the electricity was enough to bust through that carbon layer shorting it out further.

No matter the cause, there is no fix. So the melting of the servo and the shorting of the motor would have resulted in a replacement anyway.

I would stick another one on there and go again. If you are worried, order 3 DS415's or 3 DS416's and replace all cyclic servos at once. You don't want to mix and match and should only run servos that are from teh same batch.