Futaba 3150 overloaded 6,5 volts - burned !

I ask the forum experts for advice. A friend connected the Futaba 3150 to a 5-cell Eneloop pack (6.5Volt) and burned them. Can they be repaired? will it be only electronic or even the engine? What happens if overvoltage starts to short the servo? is there any store that repairs them at a decent price? spare parts?
3 Futaba servo 3150 is a nice capital to throw away!
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google translation ( answer also in german I'll try to re translate, for sure!)

Ich frage die Experten des Forums um Rat. Ein Freund verband die Futaba 3150 mit einer 5-Zellen-Eneloop-Packung (6,5 Volt) und verbrannte sie. Können sie repariert werden? Wird es nur elektronisch oder gar der Motor sein? Was passiert, wenn die Überspannung das Servo kurzzuschließen beginnt? Gibt es irgendein Geschäft, das sie zu einem vernünftigen Preis repariert? Ersatzteile ?
3 Futaba Servo 3150 ist eine schöne Hauptstadt zum wegwerfen!

Hi Mikko,

i think the buffer capacitors are shorted due to overvoltage. In a description i have seen low voltage servos, whatever that means. A repair in a shop is nowadays not thinkable, it would cost even more than the three servos. But this is normally not possible, nominal voltage of the buffer capacitors should be 9 Volt as a minimum?? Thus check first the resistance between red and black servo cable.

Best regards
Micha

Test

Test

Thanks Micha.
Servos under 6,5 / 6,6 volts smoked seriously for some seconds..... I am asking to my friend to try again, but seems they are completely dead !
if capacitor are 9V some other part in the circuit suffered the over voltage then. Probably not motor because wasn't moved.

Mikko schrieb:

Thanks Micha.
Servos under 6,5 / 6,6 volts smoked seriously for some seconds..... I am asking to my friend to try again, but seems they are completely dead !
if capacitor are 9V some other part in the circuit suffered the over voltage then. Probably not motor because wasn't moved.

Zum Vergrößern anklicken....

Hi Mikko,

that is strange. I'm using Futaba (robbe) TX/RX since more than 30 years. Also the Servos are of a good quality. Maybe a production fault. I have had never problems with the Futaba products.

Best regards
Micha

Hi Mikko,

please read the manual of the 3150 servos. Futaba explicitly reommend not to operate
the S3150 servos beyond 6,0 volt power supply. You should use a 4 call NiMh or regulated
6,0 volt power supply.

I would assume that the electronic burned down. The motor should be more robust.

Regards,
Richard

SUPER-HORNET schrieb:

Hi Mikko,
please read the manual of the 3150 servos. Futaba explicitly reommend not to operate
the S3150 servos beyond 6,0 volt power supply. You should use a 4 call NiMh or regulated
6,0 volt power supply.

Zum Vergrößern anklicken....

Hi Richard,

do you have a link to that manual. Normally due to a possible decceleration of a servomotor, a servmotor works also as a generator (regenerative energie). Thus the buffer elkos as well as the amplifiers and transistors should be designed for a higher nominal voltage as 6 volt. I'm a little bit astonished.

Best regards
Micha

S3150 spec. datasheet

S3150 spec. datasheet

Hi Mikko,

check this,...
https://www.gpdealera.com/cgi-bin/wgainf100p.pgm?I=FUTM0303

The connected supply voltage was far beyond the specification.

3150

3150

It's clearly stated in Futaba web page that this servos must be operated at 4,8 Volts. I helped my friend to fix servos in a Erwin Xl.
During this phase I used a Jetibox with 4 cells as battery, and all servos worked very well.
In my F3F I use 3150 with a Zepsus magnetic switch that offer an output voltage regulated to 5,5 Volts, just to have all possible power and
speed.
But my friend at home used a 5 cells Eneloop and the voltage ( after having burned 2 pieces 3150 in one wing!) was measured and the voltage was 6.5 V,

It's crazy to throw away 80 euros servos for this accident, but in effect cost more to repair !

I've no photos, but my friend told me that the connector was hot and servo smoked! and at the end of our common building day all the servos where correctly settled to zero ( 1500 ms) so were not forced in end course position.