my LST ran away!

[half_pint]

So.... I was running my Lst.... and it decided it wanted to go on a venture of its own, full bore... luckily into a snow bank.... before it hit the shiny new car it was aimed for........ but now every time you start it, wants to take off full throttle..... it was running competely fine before?!

any ideas??:\

 

[hpirushrvo]

try checking the carb that there is a 1 mm gap and also check that you havent acidently reversed the servo via the controler

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electric is for kids nitro is for big kids

 

[half_pint]

try checking the carb that there is a 1 mm gap and also check that you havent acidently reversed the servo via the controler

____________________________________________________________________________

electric is for kids nitro is for big kids

check and check..........

any other ideas??

 

[ThunderTiger]

Do a general radio check to ensure all setting are at what they were before the little "adventure", also, check if the servo horn got tweaked on the servo, it's also possible that the servo was damaged in the impact.

A quick way to check, is to unhook the throttle servo and plug the steering servo into the throttle channel. if it works the steering servo without issue, then you need a new throttle servo.

Not much else I can think of other than the carb linkage getting tweaked by the impact.....


Hope thats clear enough as I know I can get a bit "in depth" sometimes.

Hope it helps you sort your L(ittle) S(illy) T(ruck) trouble out

That's not meant as an insult, the "L(ittle) S(illy) T(ruck) " is aimed at how the truck behaved for wanting to run away from you....

 

[half_pint]

Do a general radio check to ensure all setting are at what they were before the little "adventure", also, check if the servo horn got tweaked on the servo, it's also possible that the servo was damaged in the impact.

A quick way to check, is to unhook the throttle servo and plug the steering servo into the throttle channel. if it works the steering servo without issue, then you need a new throttle servo.

Not much else I can think of other than the carb linkage getting tweaked by the impact.....


Hope thats clear enough as I know I can get a bit "in depth" sometimes.

Hope it helps you sort your L(ittle) S(illy) T(ruck) trouble out

That's not meant as an insult, the "L(ittle) S(illy) T(ruck) " is aimed at how the truck behaved for wanting to run away from you....

It was the throttle servo.... looks like it needs to be switched.... its the 3rd JR Racing servo we've been through in the last 3 months...... (lol and it is a Little Silly Truck.......)

 

[ThunderTiger]

glad you know what it is now.

Have you considered a futaba or Hi-Tec server by any chance ?? both good brands by all account. Then of course there are the tower hobbies home brand.............

There are a lot of servo's of a lot of different brands available and if you have been through 3 JR servo's maybe it is time to try a different brand maybe ?

 

[half_pint]

yeah we're going to a different brand... the JR racing are what were on the trucks when we got them.... thanks for the help!!

 

[ThunderTiger]

Not a problem.

I had the same thing happen on my 1/8 buggy once, had a bad hit at full throttle on the front end, repaired all the damage only for it to take off the next time i ran it. Quick check revealed the servo had been damaged from the previous impact.

Seems i'm becoming a walking mine of info on a few things r/c............................

Can I ask a quick question ? Do you run fail-safes or do you run 2.4ghz radio ?

 

[olds97_lss]

Just an FYI, you said you hit a snow bank... which suggests your running in wet conditions (snow melts ). Water will ruin a servo pretty quick and 9 out of 10 times, the throttle servo goes first due to how they are mounted. They are mounted upright and the servo horn/output shaft pretty much creates a funnel that water runs down into the servo through. It runs through the motor, then saturates the ECB inside causing the servo to fry, fail or freak out in general. Also, 9 out of 10 times, when they fry, they fry and wander to wide open throttle. I have yet to have a t/b servo die on me and not go wide open. Regardless of a fail safe (FS) or throttle return spring (TRS), they always tend to overpower the spring and since water isn't a loss of signal or drop in voltage, the electronic FS doesn't kick in. Even if it did, the servo is dead and won't respond.

If you insist on running in wet conditions (as I do), I highly suggest you do what I do, get water resistent servos. You can spend a lot or a little, but if there isn't an o-ring on the output shaft, it will get water in it and fry. Trust me... I've burned up many because I run in snow or dew soaked lawn. I also hit my rigs with a hose at the end of a dirty bash session to clean them up to keep the dirt outside. You can try sealing them externally by using plasti-dip, balloons and an o-ring under the horn, but also IME, that doesn't hold up nearly as long or as well as servos built with o-rings where they need to be.

The stock t/b servo in the LST is a Z270 wich runs around 50oz of torque (weak) and isn't metal geared. I tend to lean towards a more expensive, stronger (torque and gears) and water resistant servo than what stock is. T/B servos in MT's last longer if you buy one that is too strong for the job. Leaning heavy on the brakes a lot overheats a weaker servo and they crap out as well because of it. MT's require a lot of heavy braking.

The cheapest route is to go with traxxas waterproof servos.
High torque, non-digital, waterproof: 2056
High torque, digital, waterproof: 2075

I want to say the 2056 runs around 90oz and the 2075 is around 125oz. Neither are metal geared though, but out of the two, I'd pick the 2075 for it's strength.

If you want to spend a decent bit more, I buy the Hitec 985MG. Great servo for the money. Strong, fast and as water resistant as traxxas's "waterproof" servos are. Total overkill for a t/b servo, but they last a long long time. The one in my aftershock is 3 years old. The one in my savage is 2 years old. Both are used as T/B servos.

Even with the o-rings on the case, screws and output shaft, I still take them apart, clean all the areas the o-rings are and put a light coat of sensor safe RTV to ensure a good seal. I also work RTV into the seal/plug that the servo wire runs through and seal around the edges of that plug with RTV. Make sure to use sensor safe as non-sensor safe emits a acidic gas as it cures which causes electronic bits to corrode.

Sorry, will end the rant now.
Good luck!

 

[ThunderTiger]

thats not a rant olds, thats pure gold in a post !

 

[half_pint]

don't appologize for the rant olds I quite enjoyed the information and found it very useful!!

Thank you!!

 

[ThunderTiger]

half pint, you have to watch out for olds, he likes yanking ya chain about his "rants" cos they are always darn good posts with a mine of information in 'em.

 

[half_pint]

half pint, you have to watch out for olds, he likes yanking ya chain about his "rants" cos they are always darn good posts with a mine of information in 'em.

LOL so far you guys all have a bunch of useful information.......

 

[olds97_lss]

Well, usually after I realize I've typed 7 paragraphs, thrown up a diagram and "how to" pictorial or video... I realize I just got on a soapbox and preached a sermon that no one asked for. But, by then, I've spent so much time typing... that I just post it anyway.

Hope it helps!

 

[ThunderTiger]

olds, ANYTHING you post like that is a help, hell that even helped me a lil bit, the part about the sensor safe rtv. never new that trick, i just used plain old silicone before.....

 

[neobart]

There's nothing wrong with JR servos, as long as you stay away from the z270's. On all three LST trucks I've had through the years, only one 270 is still kicking. The 590's on steering aren't that much better. You can find z650's for as little as 40$ on ebay and some web shops, a decent metal geared servo IMO.

 

[olds97_lss]

I'm with you on the quality neobart, just not on the water resistance. I'm still running the original 590's on my aftershock (3 years?) and have run them in snow/wet without issue, but they are mounted with the top side down. So water is obviously less likely to get in them.

I've burned up 590's and 650's though as t/b servos in the past due to water damage. They didn't fail as catastrophically as a few futaba's I burned up (it actually burned the board inside), but they did fail and didn't work right once dried out.