Twitchy servos

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Oldford

RC Newbie
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I have 1/5 th fg marder ,I have just replaced steering servo Futaba s3306 and throttle servo tactic tsx40 and receiver Futaba r162je and the on/off switch, I have 6.4v in battery which is a Sanyo race 2000 when checked with a volt meter. When I turn it on both servos twitch a lot and then settles eventually, when turning the steering which is not that responsive the throttle servo moves as well it’s not a lot but enough to think that it’s not right.

I also have new batts in the controller which is a W2 AR. I also have an ripmax xtra failsafe on the throttle but throttle seems worse when it’s attached. The new replaced parts were due to a power switch failure that shorted out and fried wires ,the parts I didn’t change were the chips and battery pack. When wheels are on the floor there it doesn’t seem to have enough power to turn the wheels only when they are lifted , could this be my battery pack?

I’m pretty new to this and all these bit ain’t cheap thanks guys
 
The twitching indicates a brown-out effect (a voltage sag). usually. The other thing that I saw was that the link to the servo stated that it had nylon gears and the review was negative. That's a big red flag to me.

The first thing that I'd recommend is trying a larger capacity receiver pack. Something similar to this: http://www.davesmotors.com/Venom-6V-5000mAh-5-Cell-Hump-Receiver-NiMH-Battery-for-Gas-HPI-Baja.html

Dave's Motors is a great place to find parts and upgrades for 1/5 scale models like your Marder or my Baja 5b at a reasonable price.
 
Thanks for the reply, the servo is actually mg ,before I had this problem with wires melting it was fine but did not have metal gears and I sheared some teeth of the gears I changed the servo to another I had which didn’t work , I then had this short and changed everything and now this problem. What does hump mean in the description?
 
Would these do the job?
FB31C680-820B-4E95-9271-A18C129A2092.png
 
if it is the same style (Hump/Flat) as what was installed should be fine, i am unfamiliar with that brand though.
 
I'm assuming your FG isn't an electric conversion, but rather a typical 1/5th scale that runs on mixed pump gas? If so, I'm kind of surprised you haven't had an issue always with running an AM radio as the ignition system on a 1/5th scale can put out quite a bit of electrical noise when running.

I'm also surprised a 100oz servo is stout enough for t/b on a 1/5th scale. When I had a HPI Baja 5B SS, I ran a hitec 985MG which was 170oz for t/b and it would do the job, but worked hard.

You could try getting a glitch buster cap which may help with brownouts and help filter out some of the electrical noise.
https://www.amazon.com/Racers-Edge-Glitch-Buster-Capacitor/dp/B0077R5I4M
 
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I have just received a new power pack and fitted it and it’s still the same, I have changed everything bar the crystal chip thing could that have been damaged due to the wiring issue I had ? As it has been working of a sorts. I’m getting more throttle response than steering and I’ve noticed that the new Futaba MG steering servo twitters as if it has a birds nest in it . When everything is powered down the steering turns easy so there is nothing catching, help help help as this is p*******g me off.

903FE359-F802-40A7-BB39-9BBD48DE139E.jpeg
 
I have just received a new power pack and fitted it and it’s still the same, I have changed everything bar the crystal chip thing could that have been damaged due to the wiring issue I had ? As it has been working of a sorts. I’m getting more throttle response than steering and I’ve noticed that the new Futaba MG steering servo twitters as if it has a birds nest in it . When everything is powered down the steering turns easy so there is nothing catching, help help help as this is p*******g me off
i would highly recommend getting a 2.4ghz Rx/Tx to swap in there. especially nowadays the old crystal systems are pretty twitchy, and todays day and age alot more interference.
they are also really finicky with damage/length changes to the antenna on either the receiver side or on the transmitter side. can get a flysky GT3B for around 40$ on amazon (i would not recommend getting off ebay, there are a few that are DOA and amazon has really good return policy, less hoops to jump through.) there are some other cheap ones as well which should work fine, but i haven't had any experience with them.
 
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