RC-NUKE

I have used Ace RC's S2008MG high-torque servo for my FG Ferrari F1 (1/5th scale) fomula car, for the throttle/brakes. I have checked connections with power supply rail polarities and signal and ground cables before connecting to battery (6000mAh 5-cell NiMH).

The first time I powered up, there was a burning smell and smoke from the servo back plate and it was burnt out. I took it back to LHS and they gave another exactly same servo as warranty replacement.

Like the previous one, the second servo also had identical burnout with unbearable smell of burning plastic and circuitboard and smoke. Luckily, both incidents occured when the car was at the pit... thank the Mother Nature it didnt happen while this monster was running......

Can any one share your thoughts as to what could have happened and how I can prevent this repeating the third time? Also, could someone suggest a better servo as replecement?
I have ordered Airtronics 94361Z metal gear high torque servo with metal heatsink body... Does anyone have any reviews on this servo and any advised for me?

Thanks much in advance.

RC-Nuke

dc2 man

hello

firstly for its size you cannot get a better servo (unless you spend 100s of euro) for it price and size it is excellent little servo.

now my opinion is your battery is too powerfull and is just frying it,i use 4500mah packs and have never had any problems with mine.

unless you got power supply going to your servo reversed,now this would also burn it up,though you did say that you checked the connections first,i would double check,man i think its not able for a 6000 mah pack......

they are the only things i can suggest to you,have you it plugged in the correct way in to your reciever?

Foxy

ACE DS1015. Period.

EDITED:Reading your post again, Iactually have to concur with DC2 man, Ithink you probably have something connected up the wrong way. Make sure the black cable of yournext throttle servo sits next to the black cable of any other WORKINGservo (in the receiver, and not next to the white SIGNALcable). You're not using a 7.2 or more volt battery are you? Cos that may cause it as well.When you do get around to making one work for more than ten seconds, make sure you are setting the end points appropriately, because if not, your servos will continue to suffer the same fate.

dc2 man

actually just after realising that the one foxy mentioned is the one i have.........

best of luck with it.

RC-NUKE

DC2Man and Foxy, Thank you for the response and your thoughts. Being a Physict, I double and triple checked the battery voltage (5x1.2V=6V) and polarity of power supply rails and the signal line of the Servo and aligned with the receiver and steering servo leads. Ialso heard from another LHS that another person returned a similar Ace RC Servo with dentical problem.

I have ordered the Airtronics 94361Z servo and will be building a current limiter to 1 A max allowed current for servo. Also, unless the servo circuit draws a larger current (Heavier load), the battery just does not pump in a heavier current into servo. Now, leads me to think there could be a manufacturing deffect; two servos burnt out under identical circumstances on my side and an LHSsays similar occurence repeated with another.

I will keep you guys updatged on the performance of the Airtronics version.

Thanks for your feedback.

Foxy

Sounds like a definite manufacturing defect then. You shouldn't need a regulator of any kind with the airtronics, and if you do employ one, it should be a voltage regulator not a current regulator, as our sub C cell packs will often put out quite a bit more than 6v when fully and freshly charged. If you regulate the current you are just going to limit the torque of the servo (effectively reducing braking) when all you need to do is protect it from voltage spikes. It is not normal for servos to burn up, only the most sensitive ones need regulators of any kind. I say don't bother with a regulator, set your end points carefully, and I think you'll be fine.