Go Back  R/C Tech Forums > General Forums > Radio and Electronics
Curious Futaba S9451 Servo Issue >

Curious Futaba S9451 Servo Issue

Curious Futaba S9451 Servo Issue

Reply

Old 04-29-2007, 10:48 AM
  #1  
Tech Elite
Thread Starter
 
sosidge's Avatar
 
Join Date: Dec 2001
Location: Bristol, UK
Posts: 3,913
Default Curious Futaba S9451 Servo Issue

During today's racing I had a weird problem with my servo that I have never experienced before and wonder if anyone else has.

It's a Futaba S9451, only used at a few race meetings, so a high quality metal-geared digital servo, partnered with a Futaba PPM receiver, Futaba 3VC tx and a Keyence speedo, in a TA-05R.

As I came around a sweeper the servo did not come back to centre. There may have been very slight contact with the track markers as I came around, not enough to crash the car though.

Obviously I am parked up by the side, assuming that the servo saver had jumped on the servo as the servo was still moving fine, just offset.

Got back to the pit, switched off the car and transmitter, had a look at the car, mechanically it all seemed fine.

Switched the car and tx back on and the servo returned to the correct centre with correct travel again, and it was perfect for the last race of the day with no adjustments at all.

Any thoughts?

Seems like the servo temporarily "forgot" its correct centre, but I have no idea what would have caused it, so I am a bit worried that it might happen again.
sosidge is offline  
Reply With Quote
Old 04-29-2007, 11:21 AM
  #2  
Tech Apprentice
 
ff01's Avatar
 
Join Date: Dec 2006
Posts: 76
Default

WOW

exact the same thing happend whit my servo today......but i run Hitec.
what can it be ?

//ff01
ff01 is offline  
Reply With Quote
Old 04-29-2007, 11:29 AM
  #3  
Tech Champion
iTrader: (13)
 
Korey Harbke's Avatar
 
Join Date: Oct 2002
Location: Redmond, WA
Posts: 6,164
Trader Rating: 13 (100%+)
Default

I know this may seem kinda dumb... but check the gears. The futaba 9451 has one plastic gear in it. I know it came back to normal... but I would still check it to make sure.
Korey Harbke is offline  
Reply With Quote
Old 04-29-2007, 05:25 PM
  #4  
Tech Elite
iTrader: (138)
 
SammyZ's Avatar
 
Join Date: Sep 2005
Location: New England
Posts: 3,045
Trader Rating: 138 (100%+)
Default

Wow! I just bought S9451 and there is a palstic gear in it? Wtf? why?
SammyZ is offline  
Reply With Quote
Old 04-29-2007, 07:49 PM
  #5  
Tech Champion
iTrader: (13)
 
Korey Harbke's Avatar
 
Join Date: Oct 2002
Location: Redmond, WA
Posts: 6,164
Trader Rating: 13 (100%+)
Default

A lot of metal gear servos aren't entirly metal gear. Just look at the new high end ko propo servos. They usually have one plastic gear. Some companies have all metal gears though.

-Korey
Korey Harbke is offline  
Reply With Quote
Old 04-29-2007, 09:08 PM
  #6  
R/C Tech Elite Member
 
JayL's Avatar
 
Join Date: Mar 2006
Location: Ca
Posts: 3,043
Default

probably a bad tooth..

the one non-metal gear is to stop the circuit..all metal gear train will cause glitching...

some of the new KO's have a hybrid gear, stronger than plastic but non-conductive
JayL is offline  
Reply With Quote
Old 04-30-2007, 06:04 AM
  #7  
Tech Elite
iTrader: (9)
 
Rick Vessell's Avatar
 
Join Date: Jan 2002
Location: Central IL
Posts: 2,338
Trader Rating: 9 (100%+)
Default

Sosidge,

Sounds like a bad tooth on the plastic gear. I've had the same thing happen and it's been the plastic gear. Like Jay said, an all metal geartrain can cause glitching and you can blow out servo motors if you don't have a built in failure point.

Socko
Rick Vessell is offline  
Reply With Quote
Old 04-30-2007, 08:36 AM
  #8  
Tech Elite
Thread Starter
 
sosidge's Avatar
 
Join Date: Dec 2001
Location: Bristol, UK
Posts: 3,913
Default

Had a good check of the gears, all seems well, hoping it was just "one of those things" and won't happen again.
sosidge is offline  
Reply With Quote
Old 05-25-2007, 07:43 AM
  #9  
Tech Elite
Thread Starter
 
sosidge's Avatar
 
Join Date: Dec 2001
Location: Bristol, UK
Posts: 3,913
Default

TTT see TA05 thread for more on this issue.
sosidge is offline  
Reply With Quote
Old 05-25-2007, 11:25 AM
  #10  
Tech Regular
iTrader: (9)
 
94_snake's Avatar
 
Join Date: Mar 2005
Posts: 325
Trader Rating: 9 (100%+)
Default

One thing for you to check on... I had something similar happen to me running a 9550. As it turned out, the screws that were holding the plate on the steering system, were binding with the chassis. It would stick during the race, when I brought it back to the pits, it would seem fine. I replaced the countersunk with button head, and dremmeled down the chassis a little, and never had a problem with it after that..

So it may not be the servo problem at all, just a binding issue. Check that out and let us know if it worked...
94_snake is offline  
Reply With Quote
Old 10-09-2007, 06:30 AM
  #11  
Tech Regular
iTrader: (-1)
 
PeteB's Avatar
 
Join Date: Feb 2006
Posts: 477
Default

I had a similar issue with a 9541 and upon investigation it was the plastic gear that was broken.

Does anyone know if I can get a replacement plastic gear. It seems kinda pricey to have to buy all the gears (AU$75 = US$60) when all I need is one tiny little plastic gear...

are there any others that will fit??

Pete
PeteB is offline  
Reply With Quote
Old 10-09-2007, 08:22 AM
  #12  
Tech Elite
iTrader: (2)
 
rtypec's Avatar
 
Join Date: Jun 2002
Location: SoCal
Posts: 2,978
Trader Rating: 2 (100%+)
Default

I think the plastic gear set from the S9151 and S9252 contain the plastic gear your looking for and cost a fraction of the price. I watoozied my S9451 this weekend and ordered some S9252 gear sets to repair the servo with. I should know for sure sometime next week.
rtypec is offline  
Reply With Quote
Old 10-09-2007, 09:32 AM
  #13  
Tech Fanatic
iTrader: (16)
 
|JayFlores|2's Avatar
 
Join Date: Feb 2007
Location: parañaque
Posts: 910
Trader Rating: 16 (100%+)
Default

this also happened to me using the same servo..problem is the servo horn. maybe the grooves/teeth inside it are already stripped. thus, making it not go back to center.
|JayFlores|2 is offline  
Reply With Quote
Old 10-16-2007, 04:23 AM
  #14  
Tech Master
 
Join Date: Feb 2007
Posts: 1,451
Default

I have a friend who this has happened too. He says these servos never go back to center after a bad crash.
samstheman2 is offline  
Reply With Quote
Old 10-16-2007, 03:01 PM
  #15  
Tech Adept
iTrader: (3)
 
kevinmajor's Avatar
 
Join Date: May 2007
Posts: 192
Trader Rating: 3 (100%+)
Default

Think of that plastic gear as a BLOW OUT GEAR. I'm pretty sure Futaba designed it that way so if you whack a barrier or something the gear will strip before you blow out the entire gear train or the servo motor. You can get a five or six pack of just the plastic gear for like 7 bucks.
kevinmajor is offline  
Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service