RC servos gone bezerk

[RobertN]

I have a couple RC sailboats, posted here before. I was getting them ready to go in the car; I have opportunity to sail them at a work party at a lake tomorrow. I always check batteries, operation etc before I pack them up.

On my smaller boat, the servo's freaked out! Started moving back and forth even though I was not moving the remote control(turned on radio before servos like usual). I shut everything off, and opened the hatch to see inside. Turns out the AA batteries for the receiver and servos leaked, but it was not much, and was contained to the battery tray.

I put another battery pack in, and tried again. Same thing.

I am building another boat. I used the radio and receiver for that boat, and plugged it in to my existing boat. Servos still moved back and forth, limit to limit.

I hooked up the original radio and receiver, but used the spare servos from the new boat. They worked ok, but it appears one channel on the original receiver is dead.

The original receiver was always in a sealed bag. The boat was dry inside after the last use a few weeks ago. The receiver/servos were switched off. I know the batteries leaked, but they were isolated from the servos/receiver by a switch(which still operates fine).

Ever seen anything like this before?

The small boat in the picture is the one having problems...

 

[tommu56]

Some times in my planes if you are too close it wil do that.
The rf signal go's in the signal line of the servo and messes it up
Do a range test.

tommu

 

[Blagadan]

Have you tried removing the crystals and pushing them back in? I know my heli had a similar problem one time but by re fitting the crystals sorted the mad servo problem....

Or there might be interference near by causing the problem? mobile phone in your pocket? Garage opener near by?

If you can put in a different set of crystals with a different frequency, that might work for you...

My cel phone makes my heli mis behave sometimes. If someone rings me and I have the phone in my pocket when the heli is in the air, it goes a bit mad.

 

[RobertN]

I'll try these recomendations tomorrow. My other boat(the big one in the picture) sailed nicely this afternoon

 

[Blagadan]

Forgot to mention earlier.... nice boat!

 

[riptides]

Nice boats!

Fresh batteries in transmitter and recievers? Or just recievers?

Like others have stated, range check and frequency checks? Someone else around you?

Let us know how it turns out.

 

[RobertN]

Thank!

One use on the batteries about three weeks ago. Tried to sail at lunch time(I can go to a local lake and sail for about 1/2 hour, drive there etc in an hour). Put the boat in the water, no breeze, so took boat out and went to resteraunt

Nobody else was around. I did just like the other times I have prepped the boats. I did have my cell phone in my pocket, and bluetooth ear piece active...

I have to go to the firestation for training in a few minutes. I'll try the suggestions this evening and report back

Nice boats!

Fresh batteries in transmitter and recievers? Or just recievers?

Like others have stated, range check and frequency checks? Someone else around you?

Let us know how it turns out.

 

[Willl]

Try a different crystal in your receiver.

 

[N80]

I was real serious into RC a few years ago. Raced nitro powered 1/10 scale monster trucks. For whatever reason, I've forgotten most of what I knew but on your radio...or at least on RC car/truck radios, there should be a small dial for fine tuning the servo response. This can vary with different servos. It is called a trim dial. If it is out of adjustment the servo can twitch like that. So check your servo trim.

I used to race the nitro version of this truck:

I got tired of nitro. Would love to have this electric version but man that is quite a chunk-o-change when you include the truck, a good charger and good (dual) batteries!

 

[riptides]

We use to scoff at anything electric or things that would glide in the air.

It was all about burning castor oil and screaming fanjets.

Now-a-days it looks like electric is the way to go......

planes that is....

 

[jinman]

I have several RC boats and only one or two of them that I can operate at the same time without bleed-over between signals. They aren't really expensive, but I had hoped to be able to race them around a circuit. That plan hasn't worked out.

Recently, I took my young grandkids out to play with the boats. One of them is a very fast v-hull. I carefully held it over the water and dropped it in to keep from stepping in the mud. My granddaughter seemed to have problems steering the boat and got it into moss on the edge of the pond. My grandson went to retrieve the boat. Since he had seen me drop the boat into the water, he just pitched it. It hit the water on its side and water leaked inside. All of a sudden, the motor went full tilt and the boat took off across the pond with no response to any control. The boat ended up about 20 feet up on the bank before it stopped. The prop was toast! Since I didn't have a spare prop, our day of boating was stopped even after getting the circuit board dry.

 

[N80]

You should be able to race a dozen boats at once without crossover problems. Lower end radios and AM crystals are probably the source of your problem, but when racing trucks there are 8-12 trucks, bumper to bumper on a small dirt track with no problems.

I don't know if electric will ever do away with nitro. Lots of folks like the noise, the dirt, the oil, etc. I just got tired of all that, but especially the tuning issues. Maybe my motor was finnicky but I could never keep a good tune on it. Or maybe I was just no good at it.

In any case, brushless motors and li-po batteries are definitely going to be big regardless of what happens in the nitro world.

Robert, did you ever get your servos straight?

 

[jinman]

You should be able to race a dozen boats at once without crossover problems. Lower end radios and AM crystals are probably the source of your problem, but when racing trucks there are 8-12 trucks, bumper to bumper on a small dirt track with no problems.

The boats I bought in addition to my v-hull are Zig-Zag racers. They work great, but even with all six channels (yep, I bought 6 of them), they do crosstalk. When I turned on the remote for the v-hull, they would all go nuts. When they work, they are tons of fun. They are fast and will do high speed donuts in about a 6' diameter circle. I've never seen anything turn like they do.

Zig-Zag Racers

 

[denmansoft]

Servos going full range back and forth is a bad reciever (or connectors from Rx to servo). Most good Rx's today will not behave this way on loss of signal from Tx.
RC stuff all has multiple channels to allow races etc. with no cross talk.
Cell phones/bluetooth etc all work on separate bands, BUT.....
Harmonics both up and down can swamp other signals. The bursts of TX from cell phones at 1.8Ghz gives enough broadband noise that my computer speaker inputs act as a Ringer for my cell phone down in the low Khz.

BTW Electrics are the only way to go. My E-MAXX ( with 4 battery packs ) is fast enough that I added a trailer. I can now deliver not just a 6 Pack, but a full dozen beer by RC.
We won't talk about what the Talon will do...

 

[RobertN]

I have been so busy with work and fire station stuff, I have not been able to look at it yet. I should have time this evening.

We've had some nice breezes the last week, so I want to try and take them out this Saturday.

Robert, did you ever get your servos straight?

 

[RobertN]

I re-tested the boat this evening. I reconnected all the original components. This radio/servo combo is labeled as "Aquacraft", who makes a series of RC boats, sail, electric, and gas. It is, however, basically a relabeled Futaba Attack two stick radio, with S3003 servos.

Experiment -1 - I reconnected the original components. Powered up the radio, then the receiver/servos. Again, the servos started moving back and forth to limits. Moved about 20' away; nothing changed. Cell phone is in other room. Turned off radio, and the servos quit moving.

Experiment - 2 - Removed Aquacraft/Futaba radio/reciever. I am building another boat; I have a Hitech Ranger radio set for the new boat. I connected that radio/reciever to the servos in the boat. They still moved around. Shut the radio off, the servos stopped moving.

Experiment - 3 I disconnected the boat servos from the Hitech radio/receiver. I hooked up the sail winch for my new boat, a Hitech HS765 heavy duty servo. I also connected the rudder servo for the new boat, a Hitech HS311 plain jane kind of servo. They worked normally.

Experiment - 4 - I reconnected the the Aquacraft/Futaba radio/receiver, but connected the Hitech sail and rudder servo. Only one channel appeared to work now.

Funky receiver and servos? The receiver was in bag, sealed from moisture. The servos were not, but I have never had more than a couple tablespoons water leak in. I leave the hatch off when not in use to evaporate any water I may have missed; I wipe up any water in the boat with paper towels.

Puzzling....

Note these are basic radios, but are used a lot with sailboats.

Robert, did you ever get your servos straight?

 

[N80]

Have you played with the trim dials yet? Many times I have hooked up new servos and had to change the trim setting on the radio significantly to get them to stop switching.

 

[RobertN]

Yes. I neglected to note that in my "expieriments"

It did not seem to have an affect. Both of the boats rudders are installed pretty accurately; they did not need trim. The sails I usually have set in the center of trim adjustment too.

Have you played with the trim dials yet? Many times I have hooked up new servos and had to change the trim setting on the radio significantly to get them to stop switching.