Savox wierd behaviour

[northkona]

I have killed quite a few servos over the years but my savox sc 0251mg is doing something I havent seen before.
It seems like the pinion on the motor is spinning . Fitted on a Wraith it will not turn the wheels at a standstill on the ground, I can hear the motor spinning , no gears crunching . Lift front wheels off the ground , works as normal. At moderate speed it works fine turning full lock to lock . It still centres properly .
At the moment I have replaced the servo with another one and wondering if it is worth fixing .
Maybe a drop of CA on the pinion ? could a slipping pinion be the problem ?
Thanks for any suggestions.

[Charlie-III]

Broken tooth in the geartrain or the servo arm is slipping on the output shaft.
That is what I'd check first.

[northkona]

Originally Posted by Charlie-III

Broken tooth in the geartrain or the servo arm is slipping on the output shaft.
That is what I'd check first.

thanks for a few clues , I have an integy 2 bolt clamp-up style servo arm and all the teeth are good on the output. I just took the cover off to look for any filings etc but all looks clean. I did notice a metal insert in the secondary or idler gear in the middle of the brass gear , I am wondering if this is the culprit .I cleaned it with cotact cleaner and put a drop of bearing retainer on it , whether it does any thing I'll find out in the morning.

[Charlie-III]

Originally Posted by northkona

Thanks for a few clues, I have an Integy 2 bolt clamp-up style servo arm and all the teeth are good on the output. I just took the cover off to look for any filings, etc. but all looks clean. I did notice a metal insert in the secondary or idler gear in the middle of the brass gear, I am wondering if this is the culprit. I cleaned it with contact cleaner and put a drop of bearing retainer on it, whether it does anything or not, I'll find out in the morning.

Sounds worthwhile.
If this is an older servo (lots of runtime) the locating holes for the shafts may be getting worn out, thus allowing a gear skip.
Granted, broken/missing teeth or worn holes sometimes means the servo arm doesn't return to center.

[Theibault]

Had this happen to one of mine. It was the shaft. Luckily my LHS just swapped it out for another.

[northkona]

Bingo ! after letting the bearing retainer dry overnight , I put a drop of CA on as well , it worked for about 3 cycles before the glue let go . Now that I have screwed with it there is no warranty, the servo is about 1 month old. My next step is to try to secure it permanently , I'll try to post a photo later , I'm going SC racing now.

[Charlie-III]

Originally Posted by northkona

Bingo ! after letting the bearing retainer dry overnight, I put a drop of CA on as well. It worked for about 3 cycles before the glue let go. Now that I have screwed with it there is no warranty, the servo is about 1 month old. My next step is to try to secure it permanently, I'll try to post a photo later. I'm going SC racing now.

Actually, since you figured out the issue, I would try & contact Savox. Explain the issue, what you did and go from there. I see a 50/50 chance they will come back and say, "Poop happens, send it in and we will fix/replace it."
If nothing else, they may send a new shaft for free.

If you want to make a permanent fix (provided you don't try my suggestions or you get blown off), I would look to see if there is a way to stake the gear to the shaft, maybe using a small center punch.

Oh, have a great SC race.

[northkona]

yeah good idea , I'll try Savox its worth a shot , nothing to lose !
I was thinking the exact same repair method with a punch. Actually I thought first to try and drill a hole 50/50 in the shaft and gear and pin it but because of different metals the bit would go straight into the softer brass first .
The SC racing turned into a practice / bash session at the track due to lack of numbers , still bloody good fun tho.

[OntarioCrawler]

sounds like when my 5645mg flattened 3 teeth in the center position. works great in the air, doesn't on the ground. its out for warranty now.

[slobin3d]

I have seen and returned a Savox that had the pinion break on the motor before, it would work sorta under no load but was useless once anything was attached

[northkona]

I sent Savox a note explaining what had happened and what I had done , Joel at Savox has sent me out a new gear set to try and get it sorted out . Fantastic service !

[Charlie-III]

Originally Posted by northkona

I sent Savox a note explaining what had happened and what I had done , Joel at Savox has sent me out a new gear set to try and get it sorted out . Fantastic service !

Sounds great. I've never dealt with Savox, so I have no clue on how it is to deal with them. Sounds OK from your comments.

Please keep us posted.

[northkona]

Originally Posted by slobin3d

I have seen and returned a Savox that had the pinion break on the motor before, it would work sorta under no load but was useless once anything was attached

this is a bit different , it wont turn the wheels on my wraith at a standstill but while its moving its fine , reaching full lock, kinda like a slipper built into my servo ! NOT the hot setup for crawling !

[northkona]

After a near record 3 weeks for my box of new gears from savox to arrive , they are installed and working fine. ( USA to Australia !) The culprit was the skinniest gear in the middle , the brass gear that was pressed into the steel one had come adrift .
Massive thanks to savox for their service ,a quick note to them and the parts were in the mail , highly recommended.