suprapilot

Hello,

I have a nitro sv27..The boat is pretty new ..only about 12 tanks of gas so far. I had another sv27 that was replaced under warranty (thanks aquacraft) and thats one didnt have any radio glitches or anything and i had that one for a while.

I noticed on this boat only the steering is very twitchy.. The throttle servo is perfect and it doesnt ever twitch or anything...I have replaced the steering servo and the receiver and put brand new batteries in the boat.

I still have steering problems ....It seems that sometimes it almost looks like the servo is struggling to move the rudder to turn right.

Also when the rudder does turn it twitches alot.. Sometimes it turns more then other times....this is very bad when trying to drive the boat because sometimes it turns so sharp it spins out and sometimes it barely turns at all...and the whole time this is all happening the throttle servo has no problems at all...not one twitch or out of control movement.

The only thing i havent replaced is the crystal. Does anyone think the crystal is just bad?? Can that even happen??

Anyone have any ideas..

I know i can upgrade the radios but i dont wanna do that just yet

Thanks in advance
Anthony

Jerry Dunlap

Does the servo "twitch" when the engine isn't running or just when the engine is running? If it's ok w/o the engine running, it could be some vibration issue. Is the rx warped in a protective layer of foam?

JD

Dan S

do you have another servo you can use to check if you have a bad steering servo?

you can also switch the servo's around just to check.

also make sure that the steering push rod is not binding or something rubbing making the servo struggle.

Dan.

suprapilot

^^ I did notice a little binding at first...I noticed that from the factory they seemed to have glued the rubber boot in he wrong spot so it was restricting the rod slightly, but now my rubber boot is open and water could leak cause i had to move it to let the rudder move more freely....

That didnt totally fix the problem...The servo is twitchy when the boat is running and when its sitting in my room off... Its not so much that the servo is struggling, I thinks its more just the twitches that is making it seem like its struggling casue its not one smoothe motion when i turn the rudder...It turns, but its not fast and easy like it should...

I got a brand new servo and receiver from aquacraft, and replaced them both and put fresh batteries everywhere..and i still have a twitchy rudder...

The only thing I did not change was the crystal...That is the original that came with the boat...

How much are they and can i just buy them at my LHS or do i need to special order my certain freq atc atc..

this is the last thing that i can think of to change, hopefully it works..If it doesnt work i will have all new electornics and the same old problem...

I did notice when i took the crystal out and put it in the other way the twitching was slightly less...SO hopefully thats a sign.

anyone have any other ideas...and what can i do with that rubber boot??


Ant

Dan S

Ant,

its not impossible to buy a new servo or receiver that is defective.
before you spend more money on a set of crystals only to find out that it wasn't the problem do a bit more troubleshooting, connect your throttle servo into the steering and your steering servo into the throttle at the receiver and see what happens.

if the servo that use to twitch has stopped and its now the other one acting up, then its a receiver/crystal problem.

if the servo that was acting up is still acting up regardless of where its connected, than its a bad servo.

if you replace the crystal, buy the as a set.
crystals you require depends on what color your SV27 is:

Channel 62 - white, AM 75.430Mhz
channel 64 - blue, AM 75.470
channel 68 - red, AM 75.550
channel 70 - yellow, AM 75.590
channel 72 - green, AM 75.630
channel 74 - orange, AM 75.670

as for the rubber boot, you can get them from towers or a replacement from your LHS.

Dan.

suprapilot

^^^ thanks..i will try this and see how it goes...If i rememeber i think i did thi with the old set of servos and it still did the same thing, but im gonna do it again just to be sure. If not im almost 99% sure its gotta be the crystals....I did check on prices and the crystals arent too expensive....maybe i can ask aquacraft for the last time for a new crystal....i just dont feel like waiting any longer..i missed 2 of the last races of the season becasue of this [:@]


ok thanks again ill let you know if it works

thanks

suprapilot

soo I switched the servos around on the receiver and sure enough, now the throttle servo is the twitchy one and the steering is perfect....Is this a bad crystal??

Also I notice that one of my servos seems to buzz a little bit when its turned fully to either side. I notice that the throttle servo at full throttle or full reverse, is make a buzzing noise like its still trying to push more on the throttle...the steering servo stops making any noises when its fully turned in either direction..
This just seems like I will burn out the throttle servo faster or something...IS this normal?

Dan S

one problem eliminated.

now that you know that your servo's are not the problem.

a servo can buzz sometimes and yours looks like its buzzing when the throttle is fully closed and fully open but the servo is still trying to go further.
try adjusting the throw/travel for that servo, you want the servo to be at the end of its travel when carb is fully closed and open, you don't want to have the servo to keep on over pushing/pulling for nothing.

now for the problem, its either or, a bad receiver or a bad crystal.

you could replace the one that is less expensive or if you can, borrow a set a crystal first.

Dan

suprapilot

thanks

Im gonna try changing the crystal first since i already have a new receiver in there and the problem wasnt eliminated yet...I do have the original receiver that is pretty new that came with the boat..i switched back to that and it was exactly the same...I do notice that when i move the crystal or turn it around the problem either gets worse or better depending on which way i plug it into the receiver..Im thinkin this might be the clue that its a bad crystal instead...

suprapilot

ok so after changing the receiver and testing both servos and realizing that nothing was helping the twitchy steering I had thought I narrowed my problem down to the receiver crystal..so i ordered a new one and i finally got it, and put it in and the problem hasn't changed one bit.....

Sooo anyone else have any suggestions as to why this is happening...

My two thoughts are..1. The crystal in the transmitter is the only thing that i havent replaced and maybe that is the problem, but why would that affect just the steering and not both servos?? and if i switch the wires the throttle servo is now the twitchy one...

2. Since i have the worst luck on the planet I believe i probably got a bad receiver again from futaba..but then again the same problem on two totally different/new receivers??? IDK about that one..

anything else i can check...

thanks again
Ant

twindaddy66

I had twitchy issues too, but only when I made contact with the engine and the glow plug starter, but no problems when running. Is this normal?
I plan to swap out to a Futaba 2.4GH system in the spring .........

suprapilot

^^^ yeah thats totally normal..it happends to most rc models ...mine does it when i turn the steering servo..it starts to twitch...any other time it is fine

Barticusmax

Howdy, It seems that you may have 2 issues. 1, you switched the servos, and the problem followed the servo? probably a dirty pot on that servo.
Other, MOST LIKELY cause, is metal to metal contact on the boat. Metal pushrods? Metal clevises? Metal rudder arm? ABSOLUTELY ANY metal to metal contact can cause glitchy twitchy interferance!! I know, doesn't seem likely, but TRUST ME, after 35+ years of flying, every time I hear about oddball glitches like this, someone has a metal clevis on a metal carb arm, or worst case I have seen was a metal pushrod, metal clevis, on a metal rudder arm. Try a plastic clevis, but be sure you have the strength needed. Wiggle any metal-metal contact and see if that causes the twitching. This issue is usually way worse when the engine is running, adding vibration to the mix.

Vertical3-D

My Feedback: (20)

twindaddy66, you will love a futaba 2.4GHz, I bought the 3PM and will never put anything else in a nitro or gas boat again, its so steady and smooth, no more glitches, no more checking whos running what frequency when running multiple boats...well worth the money for all the adjustability you get and and the built in fail safe and also a third channel for future use...and suprapilot you may also want to upgrade, then if you sell the boat or get another one you can keep the good radio for that...also off topic, is your username referring to the plane that was out way back in the day called the supra star...if so my dad had one when I was little, I believe we still have it(in 4 larger pieces)a snap roll at highspeed dislodged the rx pack and caused it to auger in at over 100mph