Model Boat Mayhem
Mess Deck: General Section => Beginners start here...! => Topic started by: stevept109 on August 24, 2008, 11:10:01 pm
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Help me !!!!!!!!!!!!!!!!!!!!!!! ::)
I have just bought a CEN Aquajet fitted with a 600 BB turbo motor and a Jeti JES 600 Navy E.S.C. Took it to the lake for an outing and all was fine. Nice and quick went very well indeed (even with my limited knowledge) this was last week
Problem is i bough it home recharged the batts and sorted it all out (cleaned and greased etc) Took it out today and to my horror she just wont go in a straight line. Ive set the rudder straight and with a little throttle OK. Then if i try to accelerate she just Vere's off to one side or the other. I correct on the stick then more forward stick and she Vere's off again.
What am I doing wrong, what have i done etc
Any help greatly appreciated
Steve...
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#1 please post a picture and/or video and list your equipment radio, am or fm?, etc.
#2 is the prop shaft straight and centered?
#3 is the rudder linkage wobbly?
#4 is the boat center balanced or is it leaning to one side?
#5 is the radio glitching/jittering servo?
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she just Vere's off to one side or the other
If its changing the side at which its going off to each time I'd say its probably a jittering servo as has been said above.
Does it do it only past a certain distance from the TX?
If I were you I'd stick it in the bath and have a mate walk out into the garden or something like that with your transmitter holding the throttle down and you watch and see if the rudder servo jitters or something like that, the further away he gets.
Alex
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Sorry for the delay in replying >>:-( Very busy you know 8)
Right i now have some time off so i will be taking all your comments and applying solutions as appropriate.
1. Prop shaft is straight & central
2. Rudder linkage is good
3. The boat is balanced OK
4. Think a glitching servo may be the problem.
I had a problem when i first put her on the water as by if i tried to accelerate and turn the boat would just stop until the rudder was back in the central position. I changed the receiver batteries (for new ones) but it still did this even with the TX just a few inches from the boat.
Then , and I'm not sure if this is OK , I attached the RX direct to one of the power pack's. This is when it started mucking about. Could this be the problem ? Too much voltage to the RX ?
I'm still very new to all this malarkey so any advise is good.
Thanks in advance
Steve...
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Does your speed controller have a battery eliminator circuit? It sounds as though this might be the case if you latterly applied power direct to the receiver. If so and you apply power direct to the RX you will get problems. You need to disconnect the power from the RX or disconnect the middle wire on the ESC lead to the RX. This will ensure the RX is getting the correct power.
If you other problem still persists then then you may have a faulty Transmitter. :(
HTH
Doug
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if the speed control or receiver are too close to the motor (and maybe the battery, im not sure which) might glitch the servo...
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I personally think you have blow the esc,why may you ask this unit has BEC which means it does not need a separate batt pack to power the receiver as it supplies a 5 volt supply straight from the mail batts this it does internally.If by your own admissions in a previous post and I quote I changed the receiver batteries (for new ones) but it still did this even with the TX just a few inches from the boat.
So by using a spearate batt pack you have cooked the ESC been there done that had the T shirt etc,defiantly if you have connected the receiver direct to the main batts you would have put that voltage don into the speed controller and blown it sky high,sorry to be a bearer of bad news but you will have to get a new one.I suppose a certain Tech no wizard will comment further wont you.
Stavros
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you may have a point..but even cooked esc sometimes continue to work...i think the jittering problem is more with the receiver because the esc does not really connect to the servo... :-\
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But if you think about it Weeds is it worth the risk
Stavros
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Do you have any to metal to metal joints, eg. linkages?
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Martin sorry wrong way of thinking the clue is in the posting of what he did ref using his main batts direct to reciever and using a seperate batt pack to power reciever when ESC has BEC.ESc only good for the bin.Yes it might still work of a fashion but it is jshsghsh
Stavros
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Sorry for the delay in replying >>:-( Very busy you know 8)
I had a problem when i first put her on the water as by if i tried to accelerate and turn the boat would just stop until the rudder was back in the central position. I changed the receiver batteries (for new ones) but it still did this even with the TX just a few inches from the boat.
Then , and I'm not sure if this is OK , I attached the RX direct to one of the power pack's. This is when it started mucking about. Could this be the problem ? Too much voltage to the RX ?
If I read correctly that you direct connect a 5 or 6 cell pack to receiver then you need a series dropper diode(a shottky is best) absolute minmum .It is not the higher voltage that is a problem it is the supply line noise upsets a shift register chip in the recever and the servo signals are corrupted and servo swings one way at high throttle.A series diode ,in conjunction with a 100 uF capacitor inside the receiver, smooths out the high frequency disturbance by peak-detection.Same thing happens if input to bec is not maintained above 6 volts and if bec regulator is damaged.If so can be easily fixed.
You are better off with a miniature (1/3 AA) receiver pack.
Barry Park
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Sorry for the delay in replying >>:-( Very busy you know 8)
I had a problem when i first put her on the water as by if i tried to accelerate and turn the boat would just stop until the rudder was back in the central position. I changed the receiver batteries (for new ones) but it still did this even with the TX just a few inches from the boat.
Then , and I'm not sure if this is OK , I attached the RX direct to one of the power pack's. This is when it started mucking about. Could this be the problem ? Too much voltage to the RX ?
If I read correctly that you direct connect a 5 or 6 cell pack to receiver then you need a series dropper diode(a shottky is best) absolute minmum .It is not the higher voltage that is a problem it is the supply line noise upsets a shift register chip in the recever and the servo signals are corrupted and servo swings one way at high throttle.A series diode ,in conjunction with a 100 uF capacitor inside the receiver, smooths out the high frequency disturbance by peak-detection.Same thing happens if input to bec is not maintained above 6 volts and if bec regulator is damaged.If so can be easily fixed.
You are better off with a miniature (1/3 AA) receiver pack.
Barry Park
More techno-crap ::)
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Some of us can understand it Richard, you need to go to the library more often! {-)
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Sorry Colin my hobby is model building not the unintelligible theory of techno crap.
I want to sail my boats not read about the intricacies of their electric supply or be able to fill up all the postings on the forum with something only a few will ever understand or want to. O0
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Well Richard, if you don't understand it then just keep quiet rather than spoil it for others. I like to learn things rather than dismiss them as "techno crap". Keeps me feeling younger!
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Stick with it Barry, there's more than one gang O0 {-) {-) {-)
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Come on Dicky, chill out a bit, this is what we are all here for.
One guy asks a question and another is prepared to give up some of his time to help. We all help on different levels but as long as it is relevent to the one asking the question what does it matter?
I didn't understand either but I'm gald that someone is trying to help.
As they always say "If you don't like what's on telly, turn the thing off!" O0
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Hi Stevept
Is the aerial wire from your rx near the main motor ?
or has is bean cut?
aye
john
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Good post. But need more info. Where do I connect the diode and capacitor?
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BlimmeyThanks people,
Some stuff I understand some "PHEWWWWW" right over my head, but i thank you all for the help so far. I'm going to rebuild and check everything in the next couple of days and will let you how I get on.
The Ariel wire hasn't been cut nor is it near the motor.
The main problem I'm trying to understand is why when i first used the boat she was perfect. All this started after just recharging the batteries and taking her back to the lake.
Just on a side line if I have fried the ESC surely it wouldn't work at all ? In fact the ESC still seems to work fine.
Again thanks for all your help peeps i really appreciate it, Like my dad always used to say "If you don ask you may never know and you never know what you may learn in the process"
Steve...
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Then , and I'm not sure if this is OK , I attached the RX direct to one of the power pack's. This is when it started mucking about. Could this be the problem ? Too much voltage to the RX ?
Hi Pete,
I googled at the spec of said controller.
A bit more info would have spared 20 guesses. {-)
You have cuffed the receiver.It wont work without drastic surgery. :(
With a photo or flatbed scan of both sides you might be able to solder under direction but look at the cost of drop in replacements.
Barry Park
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I don't normally reply to posts like these 'cos there are much cleverer people than me to do that, but I agree with Barry that the receiver is almost certainly damaged. Me, I would hand the receiver to another modeler or model shop and ask them to check it with separate servos and battery pack, just to be sure.
The posts do show how different we all are, some of us who started in the 1960s had to learn techi stuff, making our own stuff was the only way we could afford to have radio gear. The price of a decent outfit then would be the equivalent of over £1000 now, a bit much for my paper round to pay for!
My point is that we all love model boats whether ready made or taking years of work, simple or complex, so all help is valid and appreciated. Thank you all.
Chas
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Good post. But need more info. Where do I connect the diode and capacitor?
Just follow this picture of the cheapskates's speed control as a guide
It's in there somewhere! {-)
Weeds,I'll do a line diagram or or stick a finished on in a photo if you solemly declare that is not a wind up.
Capacitor is hiding inside your receiver case.
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Hi Steve,
What's the current state of your setup?
Do you still have full control over the motor with any glitches?
Is it just the rudder servo that twitching just a little way away from the Tx?
1. Is there any possibility that water got into the receiver or rudder servo?
2. Have you got another servo just to plug in to test the rudder channel?
3. Have you tried swapping the channels over just for a test?
Interestingly, on the Jeti site there is no mention of BEC in the Navy 600 but there is on the Ripmax site?!?
http://www.jetimodel.cz/eng/hlavnien.htm
http://www.jetimodel.cz/eng/navody_en/jes_450_600navy_eng.pdf
http://www.ripmax.com/item.asp?itemid=P-JES600N
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Eh! Martin old chap!
Check the picture. It's one of half a dozen I've operated on. {-)
You can't see the repair as it's a link on the opposite side.
The others were the Acoms of the old+ - s pin sequence.There was a steady trickle from people plugging their new Acoms,Futaba,Hitec batteries into second hand boats supplied with R/C.
The one above is mine but I still maintain reversing batteries is down solvent abuse and not some silly Darwin theory by Malcolm Frary.
Barry Park
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Hi Steve,
I agree with Barry that the receiver is almost certainly damaged. Me, I would hand the receiver to another modeler or model shop and ask them to check it with separate servos and battery pack, just to be sure.
Glad Chas is ,Steve,because I'm less certain as I've spotted a potential interference problem. I'm only 66% certain you have damaged your receiver. :-\
A sure sign of damage can be found inside the case. Look at the components with a lens. If the bec components or an Electrolytic capacitor looks damaged then bec can be desoldered and bypassed and capacitor replaced.
Capacitor fault is unlikely as these usually only pop at long term overstressing.Concentrate on the larger components on the underside of the board.
If you have an ammeter ,measure the mA current consumtion with no ESC or servos. It should be within 10% of the published spec. Do it with the tranny on.Increased current shows damaged bec.
I defer to Malcolm Frary,the fast electric guy as I've just noticed your ESC is OPTO(coupled).
I don't know if JETI have fully separated the "powerpack" ground from the receiver ground or just opto coupled the gate drive.He'll know and he will also confirm that separate grounds should be avoided due to interference.
If you have no continuity,a wire link between grounds is advisable and then tie to stern tube and motor case.
You can confirm continuity with a meter on ohms range or continuity buzzer or even using a bulb,battery and wire.
Regards
Barry Park
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That happend to me :(
I had to ditch it because I knew nothing about boats then! :(