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Old 08-27-2009, 06:11 PM   #1
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Default Servo Problem for newbie PLEASE HELP

My Losi 8ight T 1.0 truggy appears to be eating servos. I bought it used in excellent condition and it has had 2 servos go bad during the first gallon of fuel. I have wrecked the heck out of it during my learning to jump. The first servo to go out just stopped responding completing and it is sacked. It was a JR z650m. The second one was a loner from a friend. It was a JR 270 and it started acting wierd and now only works for two throttle revs and then starts acting erractic and eventually stops responding. I switched the plugs on the reciever and the problem follows the servo. Also tried 3 batteries and eliminated that.

I do have an Ofna Failsafe installed on the throttle. It came with the car. I took it off tonight and problem is still there.

Could it just be a co-incidence that these servos went out?
Could the failsafe be causing them to go out?
Could I have a faulty receiver causing them to go bad?
Are these receivers too low grade to have longevity with this truggy?

Please help. I am new to this and now need to purchase a servo to get back going and maybe another for backup. Any suggestions for which to get?
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Old 08-27-2009, 06:19 PM   #2
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what brand controller and receiver do you have ? Have you set the end points on the controller so the servo is not overworked trying to open the throttle more than it has to or overworked pushing against the brakes ?
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Old 08-27-2009, 06:25 PM   #3
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I have the Spektrum DX2.0 and stock receiver that comes with the Losi 1.0 Truggy RTR.

No I have no idea if it is overworking. Is there a good tutorial on this or is there some way of telling?
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Old 08-27-2009, 06:27 PM   #4
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I had no brakes when I received the car and I changed the brakes to 125% to get good brakes.
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Old 08-27-2009, 06:48 PM   #5
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Both of those servos that you listed do not have alot of torque. I believe the 650 has like 140oz tq. It sound like you may be overworking the servos. You need alot of torque to turn those truggy wheels. I had the same thing happen to my trottle/brake servo. Get yourself a JR 9001 / 8711 something like that. I know the 8711 has 403oz at 6volts. good luck
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Old 08-27-2009, 06:58 PM   #6
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i also had the same problem, called horizon tec suport, they said the chasis is flexing,the radio tray at the throdle servo is a open on one side (bad design), they said get a kings head servo tray stiffner, look at the 2.o it is now boxed off enclosed on all four sideds, also send them your bad servos, they will replace them one time no charge
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Old 08-27-2009, 07:26 PM   #7
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Wow. Really? Could this really be the cause of my problems? The second servo did start being inconsistent and problematic immediately after landing one of the large jumps a little rough and quickly went downhill from there.
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Old 08-27-2009, 07:31 PM   #8
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Quote:
Originally Posted by Zeusdafreak View Post
I had no brakes when I received the car and I changed the brakes to 125% to get good brakes.
Yup, that'll kill a servo.

1.those servos are wimpy
2. Losi's tuned flex chassis, flexed too much, get the KH stiffener
3. Brake epa should be around 50%, you don't have to pull really hard. my brake linkage only pulls about a 3/16".
4. sound like you need to replace your pads/rotors.

friction stops the car, not servo pressure. You only have to apply so much pressure to the pads.

Think of it like this: On a bicycle you pull the brake lever to stop. If we ground down the pads or covered the brakes with grease we'd have to pull harder to stop, so hard that eventually our hands would die and fall off.

A KH servo brace, fresh rotors, pads, a Hitec 7955, 5-10mm fuel tubeing, and make sure your calipers are set tight enough that your not hitting the lever stops should solve your problem.

Last edited by Zerodefect; 08-27-2009 at 07:33 PM. Reason: Torco tastes like cherries.
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Old 08-27-2009, 07:42 PM   #9
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Ok. Sounds like a good plan. What is the 5-10mm fuel tubing for?

Also should I try and get horizon to replace my servos for backups in the meantime? I bought it used and don't have receipts.

Should I look at upgrading my JRZ650 servo on my steering or "don't fix it if it ain't broke"?
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Old 08-27-2009, 07:55 PM   #10
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Default servo prob

Try these two links and do as they say. You will need to buy a high quality servo for this car but you dont need to buy the other stuff. I ran this car several years with the 9100 and had no problems once I done this.

http://www.losi.com/ProdInfo/Files/L...e_Addendum.pdf
http://www.losi.com/ProdInfo/Files/8...ndum_LoRes.pdf
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Old 08-28-2009, 09:46 AM   #11
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I am planning today tol try the recommended fix in the Losi addendum and use the springs and longer screw for now. I plan to borrow a friends Hitec servo just to be able to particitate in this weekends activities at the track but I am nervous about screwing up another servo that doesn't belong to me.

I am still trying to decide which servo/servos to buy. The hitec 7955 is $100, the 5955 is around $50 but I honestly don't know what the difference is. the Hitec that my friend is going to let me borrow is a 5625Mg. It looks like I can get one of those for like $50. The JR 9100hvs and 9100hvt's are like $200 but again I honestly don't know what criteria to use other than the speed and the torque.
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Old 09-08-2009, 08:25 AM   #12
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First off I fixed the radio tray clearance issue with a rubber grommet and that should be eliminated.

Well I borrowed a cheap Futaba S3003 servo to get me up and going quickly. I ran during practice and Saturday. The car seems to "stick" wide open twice and we luckily were able to kill it without major incident. Someone observed what looked like the carb slide sticking in one spot and suggested cleaning.

I cleaned the slide and could not get it to stick. While I was tuning the car for another potential outing I happened to be holding the car by the wing in one hand and was giving it gas with the tx. It went not responsive on me for 3-4 pulls of the throttle and then went back to working.

After reading all of this stuff I am thinking of buying a new receiver. How in the world can this be happening to all my throttle servos. I know they arent the best(JR650,JRz270, futaba S3003=all low end servos I know) but I am reluctant to put a higher priced one in until I know what is causing this problem. I am thinking new receiver and then new high end servo but I don't want to drop the money for nothing if I don't actually need the receiver. Any help would be greatly appreciated.
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Old 09-08-2009, 09:16 AM   #13
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I would find somebody at the track that loooks like they know what they are doing to help you. i helped a guy out with his 8ight buggy that had the same issues you are having and yes his reciever was toast. he actually had a splice running into the reciever and it shorted the reciever out and made it very difficult to check the low grade servos to get them working properly. he actually shorted 2 recievers and burnt 1 battery up and went through a handfull of servos before realizing that he had wires toucing.

are you removing the battery tray while working on it every time? this guy would actually try working on his stuff(removing and installing servos w/out removing battery tray). not to be rude but im just making sure you are doing the job correctly so you get the chance to properly look over your equipment. it is also possible that you got a short running the wires underneath the battery tray on the inside of the radio tray screws/fasteners also resulting in the wires getting tangled up in the spur resulting in a short.
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Old 09-08-2009, 01:16 PM   #14
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NEVER SET ANY SETTING ON THE RADIO ABOVE 100%!!!!! this will instantly fry servos because the servo wil be trying to swing further than its full potential. you must set your epa(end point adjustment) or else you will just keep going through servos. to set your epa on throttle. you must take off the air filter and set your epa just so that your carb is open all the way. it could be 75% it could be 98%. if you have to go more than 100 you lincage isnt set right. same with steering. you must adjust it so if the wheels are turned all the way. the servo stops there.
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