Need help w/ throttle servo setup

[Plaidfish]

OK last nite after I had a visit w/ who I deemed the Ozzy family of S. Florida....I went to the track to run my buggy w/ a new throttle servo....I got the Futaba S9541.....I went to the LHS to make sure I had it set up correctly cause every time I run a digital servo for T/B it goes to poop in less than 3 tanks (the only one I didn't have do this was the 8611)....I got a lap and a 1/2 and my servo went to poop...sound like the gears are stripped.....now I don't have this issue w/ my Hitec 645MG at all...I use the same linkage and it works great...I just want more response from the servo.....the linkage is not binding as far as I can tell.....I've set my EP stops so there is no flexing on the center diff or the engine when I actuate the servo......and I centered everything on the servo when it was mounted.....I zeroed all my settings on the radio out before screwing the horn on, but the thing makes much more noise than the JR servo I have for steering....I'm using a futaba 3PM radio and I have the FM Rx that it comes w/ .....I'm also using a 1200mah pack that seems to be working just fine......WHAT ELSE CAN I CHECK cause I'm getting really pissed about radio issues.....last 3 times I went out I haven't run more than 3 tanks in my buggy......I'm bout ready to sell all my stuff and take up stamp collecting........




I wanted to move this thread here so it would get more exposure...
seems the radio forum is not veiwed as much.....
could a mod please remove my other thread in the radio gear forum....

 

[CorradoPsi]

its your endpoints. I've been running digi's for throttle in my buggy for the last 2 gallons. i did burn one out, though i suspect there was moisture in the case when i powered it up. (hitec warrenty'd it no questions asked) only set your brake epa to the point where it will lock the tires under full brake. NO more than that. and make sure your using fuel tubing or kyosho brake springs so that the linkage has some give. take off your air filter when you set the throttle and when the carb is fully open thats where you set the epa, not one click more. digitals are very differnent than analog servos. if you have the digital set to go "one click more" than the linkage will allow it, it will put 100% effort into trying to get there and burn out. analogs see that they are very close to where they are supposed to be and thier power tapers off as they get closer, which is why they dont burn out as much.

another thing that i do, is mount the servo in the rubber grommets that it comes with. they hold pretty secure but have enough give to save your servo if something else if off a hair.

 

[Plaidfish]

Man that sounds exactly like how I'm setting it up except the brake side...I might be putting a few more clicks in than is neccessary......I looked for the center diff assembly to start moving a little...then I back it off a little more...

 

[Plaidfish]

And thank you for the breakdown on the digital servo that is exactly the info I've been asking about and I get the same response from everyone, "no difference between digital and analog"......

 

[CorradoPsi]

big difference between the two. an analog will just strain, a digital will destroy itself to do what you tell it.

 

[CorradoPsi]

Man that sounds exactly like how I'm setting it up except the brake side...I might be putting a few more clicks in than is neccessary......I looked for the center diff assembly to start moving a little...then I back it off a little more...

this is wayyyy tooo much. put the car on the ground and pull it forward by the shock tower while applying the brakes. the point at which the wheels lock up, is where you set your epa. when you go to a new track either do this, or make a few passes up and down the straight and hit your brakes at the end looking for the tires to lock up. as soon as they do, thats your setting.

 

[Plaidfish]

I guess I should drop the EPA adjustment to less than what is needed and adjust it going up instead of down?
when you over torque them is it just the gears that get stripped or does it fry the controller?
and Is it hard to replace the gears?

 

[CorradoPsi]

yes adjust up instead of down, i do this for all my servo adjustments. you will notice your receiver packs last longer too when everything is just right. i typically adjust my analog servos for just a hint of pressure, but digitals must be set at the limit or below.

its usually the amplifier that gets fried. gears are what goes when there is a sudden shock to a servo. gears are pretty easy to replace. amplifiers are a warrenty claim.

 

[arawak420]

i run a digi s9450 for my trottle/brake on me savage and love it. it does make a lot of white noise but it is quick and responsive. i like futaba if i can afford it.

 

[Pinblaster]

Stick with the Hitec servos, for the price they are much faster and have more torque than anything Futaba has to offer at a higher price. I just spent 2 days researching servos to upgrade my Losi xxx-nt, so I should know. I just replaced my steering servo with a 5925MG and love it. I had a JR Z270 on my throttle pulling dual return springs (1 on the servo and 1 on the motor/carb)and never had any problems with it. It only has 49 in/lbs of torque but its on the slow side. I just changed it out with an old Airtronics 94742 that is twice as fast but only has 50in/lbs of torque and removed 1 of the return springs since it wasn't as stiff as the JR servo. I also have springs on all of my linkages and have the end points set so that the springs do not bottem out, but only collaps about 75%. I never did trust the fuel tubing idea on my linkages and even removed it from the Duracrap Nitro Evader ST I got on a trade for some electronics. I actually had to totally modify the brake linkage on it due to it binding up at half throttle.

Make sure nothing is binding and pull full throttle and flip the power switch off on your RX to make sure you return spring is working, then do it at half trottle. Use as light a spring as you need to pull it closed so that you are not over stressing the servo with spring tension. I can't add anything more to what others have said about end point adjustments, I think they have it covered. :hammer:

 

[greenwing7]

wow this was really helpful I am kinda well really new with digi servos and I think this will really help prevent me from frying one I really appreciate this post oh and just for fun I got the hs-5925 digital servo for my throttle servo on the savage as of now, working on the steering,

 

[Plaidfish]

I went through 4 hi-tec servos in 2 months...2 of those were bad right out of the box....one just started smoking one day and I couldn't find any shorts except in the case where 1 wire strand was loose in the controller board and the last one (actually the first one) was my fault......I got a JR8611 and that thing is a tank.....I'm only going to buy those from now on....well I'll still get futabas for the T/B servo.....I still have some 645MG servos that rock but I will never buy another hi-tec digital servo again......just bad QC in that dept I guess.....I found what my problem was...the grinding was just dirt under the arm, and I moved my carb linkage knob thing around too far when I changed servos.....I also elevated the throttle linkage on my servo so it is perfectly straight.....I went crazy last nite trying to make it right and just got down and dirty w/ it.....then realized I left 2 servo screws off the case when I put it back together "for the quick test"...so I have to tear it all down again tonight for saturday......will a digi servo start to let go if the battery is dying on it?...I might still have another good servo that i thought was dead.....

 

[CorradoPsi]

I'm not sure if it will let go or not. my digi servo's are on either a receiver with built in failsafe and voltage check, or on a venom failsafe. neither one lets them get drained far enough to have that happen before they apply the brakes to tell me to charge up.

 

[Plaidfish]

I had the Ofna fail safe on mine and it justreaked havoc w/ any of my digital servos so I took it off......the track I run at has gates all aeound the area so they don't get too far....and alot of the guys don't run safety switches....they seem to cause more problems than they are worth during races.......I'm getting one of the HRS receivers to see how they work and if it goes well I'm replacing all of my Rxs w/ them.....as for the servo "letting go" I had one that seemed to go to full throttle then slowly loose it's position.....I thought it was the servo gone bad.....but I hooked it up last nite and it was fine..I put a little pull on the arm to see if it gave and it stayed

 

[Pinblaster]

I got the hs-5925 digital servo for my throttle servo on the savage as of now, working on the steering,

Use the same servo (HS-5925MG) on your steering also and you will have a smooth controllable truck. I couldn't beleave how much difference it made on my Losi. I may be getting another one soon to add to my throttle. When I got mine I was actually looking for the HS-925MG due to the $10 savings on price, but the guy at my LHS didn't have any in stock and said they were being discontinued. He also told me he was running them in his heli and his Losi truck and was telling me how great those servos are and how much difference they make in controllability. Even over the HS 925MG.

 

[CorradoPsi]

ofna failsafes suck. period. i wish more people knew about it. they usually dont save you from "hits" either. i only use venoms, they are much more reliable. i never have compatabilty issues, in fact i have one on a 5925mg and it works great. i have a HRS receiver on my xray using a 5925 for throttle and a 5945 on steering. I'm using the failsafe on both channels to steer straight and apply brakes. the setup has never let me down. not a single runaway. only downfall of the HRS receivers is you must use digital servos.

 

[Plaidfish]

yeah I'm using all Futaba or JR digis from now on.....much better torque / speed ratings...I'm just now seeing the critical setup issues involved (thanks) and I think now I shouldn't have any issues.....if it doesn't rain tonite I'm gonna try my XB8 w/ th enew road tires on it......and see if I can chase out any more problems so I don't have to wait to go to the track to run it and check stuff out.....this thing is wicked fast on short tracks I want to see just how much I can get out of the top end on an RG......and also get a better chance to try different gear ratios as well....

 

[Plaidfish]

I'm running the 3PM radio....which one are you using?

 

[CorradoPsi]

same thing 3PM. i like it a lot, and can't justify a 3PK just yet.
i have an older 3PD-F that i use on my "beater" vehicles

 

[greenwing7]

Use the same servo (HS-5925MG) on your steering also and you will have a smooth controllable truck. I couldn't beleave how much difference it made on my Losi. I may be getting another one soon to add to my throttle. When I got mine I was actually looking for the HS-925MG due to the $10 savings on price, but the guy at my LHS didn't have any in stock and said they were being discontinued. He also told me he was running them in his heli and his Losi truck and was telling me how great those servos are and how much difference they make in controllability. Even over the HS 925MG.

is the 127 in/oz of torque enough for the steering set up???