Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: BroomBroom on April 09, 2009, 04:29:15 pm
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OK, I'm stuck and fed up - hopefully someone can point me in the right direction.
First, the gear:
1 x Graupner Speed 280 with (supplied) capacitors fitted
1 x Acoms Techniplus 40MHz Tx/Rx with Standard Acoms Servo
1 x Action P78 Condor 2 ESC with diode (set up to use Rx Battery for motor)
'On board' stuff currently powered by 4 (fresh) AA Dry Cells
All the above is new and was bench tested before being installed in my (comparatively small) boat.
*The only thing I did notice, prior to hooking up the ESC or the motor, is that the servo has a tendency to tick away to itself (chatter?) sometimes - there is no noticeable movement and a 'flick' on the stick usually stops it. Distance/Aerial etc. make no difference to this phenomena.*
OK, so I got my ESC this morning, plugged it into the receiver, hooked it up to the motor - and it all worked beautifully! I then popped in the plug for the rudder servo - that worked fine as well.
Then, I gently pushed forward on the motor stick and... the rudder servo then whacked itself clockwise (further than its usual path of travel) until the revs increased and then it was back to normal - same behaviour when running either forward or reverse.
If I flick the motor stick up to get mid revs or more from standstill, the rudder servo just twitches and then centres itself and behaves normally (apart from a slight drop in revs that is hardly noticeable), but any slight movement of the motor stick around the centre 'dead zone' will cause it to go temporarily bonkers - like it's making me :((
I'm pretty certain that proximity of the units is not the issue as even spread as far apart as possible the results are exactly the same.
Anyhows, there's little I can do about that as the central space in the attached photo is all I have (that will be accessible).
Sadly, I have no access to any other kit, servos, receivers etc. and I've spent the last of my pennies on this lot - so where do I go from here apart from chucking it all in the cupboard and making it a static model?
I've read through everything I can find, but nothing seems to relate to my problem, so I'm hoping somebody can shed some light for me please.
Many thanks,
Robin
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Hi Robin.
Forgive me if I missed something because I only read half of that.
Dry cell batteries are no good for receiver packs.Use NiCD or NiMH
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hi there Robin
Has your motor been adequately supressed with capacitors across the motor terminals - because the symptoms you describe are commonly associated with unsupressed motors using the same power supply - to feed the RX.
Just re-read your posting there, and I note you have suppressed your motor - so what I posted above is a load of twaddle %% %% proves to ya, I am getting too owld for posting - not reading - wake up Bluebird!!!
aye
john e
bluebird
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Hi Robin
Two thoughts. I'm not sure why dry cells shouldn't be OK to power the receiver. The difference from NiMH cells is that 4 x dry cells = 6 volts and 4 x NiMH = 4.8 volts. However I'd be surrprised (though I stand to be corrected on this) if a RX was that voltage sensitive.
Second thought. I agree that the symptoms sound like some sort of motor interference getting on the RX power supply line so my first step would be to power the receiver from a separate 4 cell pack. I doubt that the problem is with the ESC and, as you may know, the maker reads this forum so may well be along with his own professional advice on what to try.
HTH
Guy
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Well I've got as far down as the photo attachment now.
My conclusion is lack of proper suppression.
How many capacitors are there and have you earthed the motor case?
The battery issue has nowt to do with the problem but the Duracells have to go.
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hi there
Are you trying to run this model near a florescent light?
if so, switch the light off and it may solve the problem - I have had mega problems with 'glitching' only to find when I switch me florescent lamps off which are above the workbench - it cures it.
other thought check the diode is soldered in the right way around.
From memory, if you have soldered it the wrong way round, you get a different problem. Always worth a check though - and - remember with the diode in place in the speed controller the maximum voltage is 6 volts minimum 3.5 I think.
aye
john
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Brilliant - thanks guys!
OK, motor suppressed with 2 x Caps which came with it from terminals to casing only. Also, I'm not too sure that my soldered joints are that good, so first step is I'll get a 3xcap suppression kit, blag a beefier soldering iron and re-do that. As for the Duracells - yup, intention is to replace them in due course.
Dim question - where would I earth the motor case to?
John - no flourescents and the diode was 'factory fitted' by a certain FLJ - so I'm guessing it's probably OK :-)
Cheers,
R
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Is that coil of wire in the lower LH corner of the photograph the receiver aerial?
If so uncoil it and try again.
GlynnG
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You can raid any old piece of equipment but it is the (third) capacitor that does the suppression from 0 to 30MHz.That is the frequency that travels through cables into the receiver.Worry about that first and then deal with the 30+ Mhz suppression if that doesn't sort it (it will)
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Paul's ESC was built on Tuesday and tested using the hack Hitec Ranger 3 set which I abuse for everything. No problems were encountered - old Talbot knew what he was doing when he designed these things.
There is some good learning-point stuff here, especially uncoiling the Rx antenna, using rechargeable cells and fitting a 0.1uF capacitor across the motor brushes. Our stock 280 motors are virtually uncontrollable without that little cap, but purr like pussycats once you've fitted one. As Mr Speed says, that'll fix it. You could earth the motor case to the prop tube/shaft, but few folk tend to bother.
Don't extend the Tx aerial fully if you're bench-testing in a confined area but don't leave the Tx switched on for more than a few minutes with the aerial retracted.
BTW a 4-cell NiMH pack charges up to around 6v in this household. The absolute maximum voltage possible through that little ESC will be 7.5v, after which the microprocessor will turn to toast.
FLJ
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There is another possibility, I have had "duff" radio gear before both Acoms and HiTeck with similar problems as above, it could be this but, try the other sugestions first, if the problem still persists, it will be either the servo on the steering, or the RX. I have never had a snag in 30 years using normal AA batteries in an RX set up when I have used them, (many times).
Paul... ok2
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Robin,
It seems you have been given just about all the useful advice needed to solve your problems. However, I see that you're using an Acoms receiver. Not that I'm saying there is anything wrong with Acoms gear, other than it seems to be more quirky (susceptible to interference) than most other named brands. So there is perhaps one more dodge you might want to try...
See those three wires coming from the Servo (red, black and yellow)? Now take a look at the 3-pin plug end. See where each wire is retained by three plastic 'clips' on the plug itself? Make a note of the location of each wire, then gently prise each clip upwards with your pocketknife and pull the wires free from the plug. What you're aiming to do is to put a gentle twist on all three wires. Don't twist them so tight that you suffocate them, but just enough pressure which holds them together, roughly two turns per-inch., then push each wire back in its appropriate location on the plug.
Alternatively, you might try wrapping the servo wires (and all the other wires while you're at it) in silver foil. Both of these methods acts as a shield against unwanted interference and generally eliminates all those symptoms you describe.
You should probably use this as a last resort, because I'd take an educated guess that firstly suppressing your motor should pretty much cure all your problems.
Excellent work on the Broom restoration, by the way.
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Paul's ESC was built on Tuesday and tested using the hack Hitec Ranger 3 set which I abuse for everything. No problems were encountered - old Talbot knew what he was doing when he designed these things.
Well I'll go to sea!
So you saying that Mr.T was the brains behind Hitec gear?
Nope - I never knew that before. What a neat surprise!
Ooops! Hang on........
I see you've spelt it HiTeck.
Is that a typo, or are HiTeck and Hitec two different things?
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Paul's ESC was built on Tuesday and tested using the hack Hitec Ranger 3 set which I abuse for everything. No problems were encountered - old Talbot knew what he was doing when he designed these things.
Well I'll go to sea!
So you saying that Mr.T was the brains behind Hitec gear?
Nope - I never knew that before. What a neat surprise!
Ooops! Hang on........
I see you've spelt it HiTeck.
Is that a typo, or are HiTeck and Hitec two different things?
Get some sleep, dude. I'll see you at Sleepy Hollow.
FLJ
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Well thanks again gents...
I'm off to find me a capacitor!
As far as the coiled Rx aerial... I did test the system with it fully extended wafting around in the Sussex countryside whilst out of sight with the Tx - zero difference in function to being 2" away on the test bench... guess it's a consistent problem if nothing else :}
Again, many thanks for all your input - I'll keep you posted!
Cheers,
Robin
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I'm off to find me a capacitor!
Robin
Maplin Code BX03D will do you nicely - price 13p. If you can't get near a Craplin's store then give me a ring and I'll post one to you. BTW sorry for the name transplant earlier!
FLJ
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OK, Re-checked all joints, strapped a 0.1uf ceramic across the brushes as per.
Uncoiled the Rx wire, fired it all up and...
No change - exactly the same as before - even grounded the motor to the house earth - nope - makes zero difference <:(.
So is it safe to assume that it's either the Servo (which still clicks away to itself remember) or the Rx?
I've tried swapping the channels over - same result. I really don't want to send the whole unit back so I guess it's swapping bits out one at a time but where do you reckon is the best place to start?
Remember, pull the Servo out and the ESC behaves perfectly - sounds like a 'crosstalk' (or whatever the tech term is) issue to me.
I dunno, thanks for your (continuing) help...
Cheers,
Robin
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40 AM or FM?
Take it away from any computer.
Changing radio bits often cures the problem by masking the real problem.
I still think it is interference from the motor - easily tested with a bit of logic.
Edit.
Changed the battery to a rechargeable one yet.Dry cells will cause esc and rudder servo to affect each other.
Time for more effective suppression.If you had that motor as part of a radio cassette unit the radio would go bonkers.
Two 3 amp 6uH inline chokes on both motor leads and wiring the motor case back to receiver -ve and stern tube.
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It sounds like you have a dodgy servo,swap for another.
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Robin,the voltage on your power line is affected by battery and cable resistance.It goes haywire when you open the throttle.You want to concentrate on the bit between motor and esc.
The closest thing to that esc is a quarter scale servo where they put chokes on the motor supply.
If you dont beleive me,temporarily use a cassette tape motor but mind the case is connected to one of the terminals and it may turn in one direction if it has an internal diode.
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Is there a separate battery for the motor or is it ALL powered from the four cells?
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No.
The motor causes the receiver supply to be very noisy indeed.That is why I'm saying Robin needs to go the extra mile with chokes on the motor.The problem would clear up with simple capacitor suppression and twin battery operation.
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If you read the first post .prior to hook up motor and esc servo chatters,something wrong with radio gear,not motor
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The tiny tick is normal with standard analogue servos.They have a 10 deadband
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Eeeekkk! :o
Let me try to answer all the questions:
40 AM or FM? - 40AM
Take it away from any computer - Still at it in the middle of a field...
Changed the battery to a rechargeable one yet - Not yet
Two 3 amp 6uH inline chokes on both motor leads - lost me now...
It goes haywire when you open the throttle - only around the centre dead zone - once 'over the hump' works just fine
temporarily use a cassette tape motor - blimey, thought I was old - i live in a binary world
Is there a separate battery for the motor or is it ALL powered from the four cells? Nope - zero room for any more than 4xcells (or a 4xcell pack) - hence the arrangement
The problem would clear up with simple capacitor suppression and twin battery operation - hmmm see above, but if I decide to just forget about this I might try that for fun - how can something only 14" long cause so many problems? Now I know why you all build so big... :-)
If you read the first post .prior to hook up motor and esc servo chatters,something wrong with radio gear,not motor - I like the cut of your jib craftysod - it's also relatively painless to try this - think I'll make it the first second third fourth thing to try.
The tiny tick is normal with standard analogue servos.They have a 10 deadband - aaaaggggghhhhhhh
R
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Hi Mate
Have you tried to just power up the radio away from the esc and boat using the battery holder you have there. and try operating the servo in the other channel on the Rx. If you've done this my appols as I haven't quite got the jist of this thread. I had this years ago, same brand of radio. It was the +ve part on maplin batteries that was shorter than th usual Unirooss ones and they moved away from making a full connectiion all the time. Another problem is with the battery box which I had to rotate the batteries once they were in situ till they made a good connection.Modelling in full of mysteries and when you solve the prob your on top of the world. Don't give up
Seaspray
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I hate to be the bearer of bad news, but no amount of capacitors, silver foil, or even in-line chokes (when you discover what they are) will cure that problem.
In your last reply you have given three clues which weren't there in your first post. Three valid reasons why you will be forever banging your head against the wall with your present setup.
Fortunately, the answer is there already; you can glean enough info' from the clues, hints and suggestions from most of the replies.
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With 1-battery operation,the receiver power supply has a pronounced alternating voltage(no longer smooth DC) only when you open up the motor throttle.On full power the current drain from the battery goes back to DC and the servo settles down.
If you monitor a normal receiver supply, by scope, when moving a servo arm back and forth you see the ripples caused by the servo motor drain.
If you monitor the voltage when driving the motor the supply trace goes apeshit.If you add chokes to the motor it goes back to something you get with a sail arm servo.
Chokes
A pair of something like these chokes http://www.maplin.co.uk/Module.aspx?ModuleNo=3660 (http://www.maplin.co.uk/Module.aspx?ModuleNo=3660) but capable of taking the motor current should connect to the motor terminals .R.S. or Farnell do them.You can alternatively wind a pair of Ferrite beads for 6 uH 3 amp but that requires a calculation.
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Hi Rob
While i see from your comments that you don't have room in your model for two battery packs, I'd seriously suggest trying the system using a separate RX pack. I'm reasonably sure that your problems are related to using the same pack. I know it won't solve the problem long term but it will show whether or not any of the components are faulty as such. If it is the combined battery pack then we can start looking for a cure rather than chasing a fault which may not be there.
I picked up a secondhand RTR electric boat a while ago at a club sale and it had more or less the same problem. This was using my 2.4GHz gear which more-or-less eliminates most forms of interference being the issue. As soon as I put the RX on a separate pack - problem totally solved.
Guy
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Have the Duracells gone yet?
No?
Look at the resistance figure in the last graph of page 2 http://www.duracell.com/oem/Pdf/new/MX1500_US_UL.pdf (http://www.duracell.com/oem/Pdf/new/MX1500_US_UL.pdf)
You will find four rechargeable cells make a difference over partially used alkaline as you take about 0.6 ohms out the supply resistance.
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Right, I am probably gonig to add to your woes, old chap, but looking at the circuit....
You are running everything of the four dry-cells - not a problem but (you knew there was a but coming up didn't you)
One thing is that you seem to have the wire from the motor to the ESC in close proximity to the servo lead to the ESC - try separating them.
Also you seem to be running everything through those tadgy wires - not a good idea. It is quite likely that when the motor kicks into life, the voltage dropped in the wires goes up and this can cause the electronics to drop out and lose control. This is worse at the lower speed because the lack of back-emf and inertia in the armature makes the peak pulse current drawn by the motor higher.
Something to try...
Use the sortest possible wires for the motor to the ESC and ESC to the battery - 0.5mm^2 cable minimum. Route the power from the battery to the Reciever and servo separately to the power from the motor & power section of the ESC.
Wom
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Where is that diode and what does it do? {:-{
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Thanks so much for all your efforts guys!
So, I'm thinking that first I have to try powering the ESC from a separate battery pack then... great - that means that I have to rip the diode out of it? If that solves the problem, well I don't know what to do - no room for another battery pack - how come the ESC is available in this configuraton if it apparently is never going to work?
Sadly, It'll now have to wait a bit if I need to get 2 x 4xcell battery packs and charger - all getting too expensive for something that was supposed to be a bit of simple fun - are these really that essential?
Assuming that sorts it, the problem is then that I'll have a cute wee model and a working system that won't fit it - makes the whole excercise rather pointless...
Sorry, but I'm getting utterly disheartened with this - done loads of RC aeromodelling in the past with IC engines and never had a single problem - i'm surprised that the technology required for such an apparently simple set-up is so flakey.
Feeling very negative at the moment - but hey-ho I won't be beaten (I hope) and really appreciate the help you have all provided.
Cheers,
Robin
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Where is that diode and what does it do? {:-{
It is in the ESC enabling it to run in its "straight through" mode i.e. using the same battery for the receiver and motor. This was recommended for my set-up. Use of an external powerpack negates the need for this.
Cheers,
R
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Graupner Speed 280 6V (6328)
A small, powerful motor for the smaller model boat.
GRAUPNER SPEED electric motors are equally well suited for model planes, boats and car applications. The nominal operating voltage is in each case marked on the motor case for ease of identification.
Specification
Nominal voltage 6 V
Operating voltage range 4,5-6 V
No-load rpm 14000
No-load current drain 0,275 A
Current drain at max. efficiency 1.58 A
Current drain when stalled 6.8 A <<<<<<
Max. efficiency without gearbox 58,2 %
Length of case, excl. shaft 30.5 mm
Diameter 28.8 mm
Free shaft length 11 mm
Shaft diameter 2 mm
Weight 42 g
Did I say what you had was similar to a quarter scale servo?
Robin,since you have to change the batteries in the long run can you just please humour me and see what difference four rechargeable cells makes.It won't cure the problem but it will reduce it by an order of magnitude.
You are capable of V = IxR calculation
The I comes from above and R from the red line graph on page 2 of the Duracell pdf link indicates 0.15 to 0.2 ohm per cell when they are 30% depleted.You have that voltage superimposed onto 6 volts.
Changing battery and putting two small components onto the end of the motor will transform the results.
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Its getting too complicated now. Firstly the little batteries won't be up to the job for long having to power everything and the motor will steal the power from the radio, leaving a half dead boat out in the water. Seriously consider a MI-MH battery pack for the motor running only and the current battery holder for the radio. Usually if I have a jumpy servo the Tx just needs to be trimmed but this is mostly on the cars as you have to tune the ESC to the stick swing on the Tx.
Here my set up after years of trial and error Ni-cad 8.4 pack for the motor and 4 AA Ni-cads in the holder for the radio. Notice how everything has at least a few inches away from each other. The items have been pulled out of the sitting positions to let you see them.The ESC is one of the best I've ever bought and have lost the address of the chap whom supplied it.
Seaspray
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The board that never sleeps...
Yup, next stage is to run the ESC from a separate, re-chargeable supply... now if I can find one that uses 4xAAA size cells :-)
Will keep you posted!
R
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Component shop for all your rechargables address in traders list
Just remeber that Dave at Action has set up your esc to run the motor off the batt pack so suerly you wont be able to use a separate pack with that esc,and also I have had a similar problem with Acoms gear now I only use Futabe
Stav
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Gentlemen
Before you drown this poor guy in a sea of hyper-technical speculation – and before I get more annoyed about having our products’ supposed shortcomings aired in public – I have just conducted a test of a typical set-up as follows:
Tx – Hitec Ranger 3 40MHz FM
Rx – Hitec HFS-04MI 4 channel 40 MHz Single Conversion Rx
Servo – Hitec HS55
Battery – 4 x Vapex 2400 mAH AA NiMH pack
ESC – Condor 2A, running in “straight-through” mode. Motor wires are 22AWG silicon, as supplied to Robin.
Motor – Stock (Chinese?) 280 clone, with 0.1uF ceramic disc capacitor across the brush terminal connections.
The aerial wire on the receiver has been cut down to approx 150mm, with a 1mm Wander socket on the end intended to mate with a plug fitted to the whip aerial connections in my models (so it has the effect of reducing the range when no whip aerial is connected).
I ran the set-up for five minutes, moving from full reverse to full ahead slowly & quickly; moving the motor stick just to each side of neutral – so the motor was running at very low revs - and all the time leaving the rudder stick alone as well as operating it.
I could not see any trace of servo stuttering or motor glitching. Both functions operated smoothly with no cross-talk etc. In short, everything performed exactly as it should. The items tested were a totally random selection from our stock of ESCs and motors.
That’s the facts – not conjecture or opinion. Please feel free to draw your own conclusions, but can we move on, please?
FLJ
(......and, yes - the batteries did come from that supplier, Stavros!)
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Dave, thanks for the input and taking the time to rig this up and test it at your end - appreciated.
1. Never had any doubts about your ESC - does exactly what it says on the tin - PERFECTLY :-))
2. Your test rig demonstrates that a configuration precisely the same as mine also works perfectly.
3. I will get an order in to those guys for a rechargeable pack - even though I don't think it will make any difference.
4. The conclusion I have to draw from the FLJ test rig is that at least part of my Radio gear is total pants.
I'm not sure which part - should I start by swapping out the servo / then the receiver if that doesn't do it?
If so, can I use a different manufacturers servo with the rest of my gear?
Finally - am I going to regret asking this last question? If so I might just stick some pencils up my nose, rock backwards and forwards and say 'Bibble' a lot...
R
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if I was in this position now. I would take the boat and gear down to the local boat club near me a.s.a.p. There is always somebody there that could help.
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4. The conclusion I have to draw from the FLJ test rig is that at least part of my Radio gear is total pants.
I'm not sure which part - should I start by swapping out the servo / then the receiver if that doesn't do it?
If so, can I use a different manufacturers servo with the rest of my gear?
Hi there dude,
Before you start scrapping stuff, I would try sorting the wiring out - this is where I see the weakness in your setup. Even the battery should cope if you are running out of the water, though NiMH cells will be better (and cheaper in the long run)
Wom
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Just to clarify, nothing I've written was intended or should be taken as suggesting that the Action ESC was at fault. I use and have a high regard for FLJ's products and customer service. As someone who in the distant past was an electronics engineer, my suggestion of trying a separate power pack for the RX was based on the logic of eliminating the easy things first! My training taught me to try the easy things first, to only change one thing at a time and to restore to square one after each unsuccessful attempt. In an ideal world (or the world of TV I worked in) we'd usually have another identical bit of kit alongside so we'd swap boards and see which way the fault went! You'd be amazed at how many faults were due to dirty connectors and didn't show on either unit once swapped due to the fact that they were just due to dirty conectors.
Guy
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hi all
Just to put the cat amongst the pigeons, this is a very similar set up to what you have, where its an ACTion speed controller, running off the same powerpack as the RX.
If you notice, the motor IS NOT suppressed; and there is no 'glitching' whatsoever on this model when I run it on 27 mghz or 40 mghz. It has the cheapest of cheap mini-servo in the back end for her rudder and she has a cheapo scrap motor from a cassette drive in it.
The first transmitter I used was the Futaba 27 mghz Attack Sport - and then I went to SkySports 4 x 40 mghz transmitter and receiver.
The only problem I have with this model is the actual run time - that is because the battery pack is a 4.8 volt x 600 mah thing. I need to increase the mah and not the voltage.
So, I believe your fault may be in your transmitter/receiver set up that you have - Acoms are not the best in the world. So, to me, I feel it may pay you to change your RX receiver to either a HiTek or a Futaba one and that way you should get better results. Good luck with that.
aye
john
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As said in the previous post, get another make of receiver, but whichever you get, make sure you have the same make of crystals, as they are not all compatible. Pete M
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The ESC is one of the best I've ever bought and have lost the address of the chap whom supplied it.
Seaspray
The website URL is on the other side of esc.
www.modelboatmayhem.co.uk/forum/index.php?topic=13738.0 (http://www.modelboatmayhem.co.uk/forum/index.php?topic=13738.0)
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Cheers stallspeed
For the address. I also printed out the setup procedure and the site address. I also got a lot of help sometime ago from this chap. I believe he is a member
This controller is the best
Well lads I'll be going back into hibernation as i need all the time to sus out this next crane build for the Meteor.
Seaspray
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Hi all
now Ive had time to have me dinner and think and re-read original posting by Broom Broom ;)
he states 'when he plugs the servo in by itself to the RX along with the power supply, the servo 'ticks and judders' slightly for no reason'
now then...
in the past I have had this happen to myself on servos, when the servo has been a very old one which had been contaminated with fuel from an IC engine and which fuel has found its way into the variable resistor pot or
the other case was when I had a mis-match and I had reconfigurated the wires from an 'old'Sanwa servo to fit a modern day Futaba receiver;
The first problem I had with the fuel contamination in the first servo I cured by cleaning the servo out; and also the variable resistance with WD40 and then washing out with methylated spirit.
The 2nd problem , I could never cure because the servo used to just 'twitch' away and it was a mismatch. The problem became worse when I added any other servos cum speed controllers to the RX receiver.
Can you see where I am coming from here...I would be willing to put a 10 pence piece wager :D that the Broom Broom's problem has nothing to do with the speed controller battery voltage being either dry cell or niCad or wiring/suppressing.
The fault, I believe, lies in the servo and the Rx. Something Broom Broom has no control over, unless he may access temporary replacements for try out.
Plus, Broom Broom, if you can lay your hands on an 'old'Acoms servo - why not strip it down, removing the gearing and use the motor and electronics from the servo (the electronics as a speed controller and the servo motor to drive the model) same as the plastic-magic lads do. See if the fault is still there.
aye
john e
bluebird
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The small ticks,without motor,may be down to the mystery diode but you know where it is,I don't.
Oh!, I agree with you that the present set up can work.That makes three folk! ......but
....as I said in an earlier post,with a small e.g. cassette motor,which is usually internally suppressed to work in proximity to a radio, and does not have the stall figure of a speed 280............. and with NiCDs which don't drop 0.5 volts per cell with a 3 amp draw.
Sail arm and winch servos have motors approaching the power of the 280 but the one I have have single ended chokes to the motor.
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Cheers John!
Latest position is I now have a new HiTec 40MHz AM Rx incoming. This will (allegedly) work fine with the rest of my gear. So I'll drop it in when it arrives and keep you all posted.
If that doesn't do it, then I'll swap out the servo.
Stallspeed - mystery diode is in the ESC to allow it to operate in 'straight thorugh' mode - nope, ticks away even without the ESC hooked up.
Cheers,
Robin
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Stallspeed - mystery diode is in the ESC to allow it to operate in 'straight thorugh' mode - nope, ticks away even without the ESC hooked up.
Cheers,
Robin
That's what I said.
I know what the diode is for but I had Bluebird or Wombat in mind when I asked "where is it"
I was thinking the servo will tick by 1 degree (which is the finite resolution of a cheap servo) because it draws current through a diode drop.I was implying in an earlier post that this had nothing to do with the main problem and the conclusion that the servo and radio had problems were bogus.
The problem is the receiver voltage goes up and down like a yoyo and both Wombat and me have offered a solution.
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http://www.action-electronics.co.uk/pdfs/P78.pdf
stallspeed have a look at the above link for your mystery diode
aye
john
bloobs
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I was thinking the servo will tick by 1 degree (which is the finite resolution of a cheap servo) because it draws current through a diode drop.
There goes that theory into the dustbin.
over and out!
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The problem is the receiver voltage goes up and down like a yoyo and both Wombat and me have offered a solution.
And i do appreciate it - honest!
Just that when I proposed this plan of action, I was advised that the set up in it's current configuration should work - so I'm going to have a crack at seeing if I can get it to work this way first. Reason being: 1 - I won't need to mess about with the ESC (which has been proven to work perfectly as per FLJ's test rig and 2 - I'm trying to get it to run off 1 x Cell pack due to the nature of the beast.
Battery Pack incoming shortly!
Bear with me, I'm going to do one thing at a time or else my head will start spinning!
Cheers,
Robin
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Back in again....
Yay!!!!!!!!
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Stallspeed are you any relation Barry Park?
aye O0 O0
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You were thinking the same as me John, dead similar isn't he ?
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Sorry Dicky.
I must have have omitted you from the pm list when I changed last year ;)
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:-)
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Quote from Barmy Park:
"...when I changed last year"
Post Moderated
Bob
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I thought so Barry Park, Sandy Calder, Phil Edison, Stallspeed all one and the same, wonder why he needs four identities, ***Moderated*** ?
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Running an RX and a couple of standard servos should normally be perfectly OK off a set of AA duracells, assuming that all the components are in working order. The problems start when the current draw increases.
The servo works by taking the length of time that the control pulse is on and turning it into a voltage. This is compared with the voltage taken from its position sensing pot. If there is a difference, the motor drives the position sensing pot to a matching position, at the same time turning the horn, and stops.
This derived reference voltage is a percentage of the servo supply voltage. If this is caused to vary, the servo will try to drive. This will put a load onto the supply voltage and cause a variation which will be seen as a demand to re-position. Just one tiny twitch can start the thing interacting.
If the RX pack is supplying everything, use NiMH rechargeables. Their voltage is less liable to sudden fluctuation. At the same time, check out the lead resistance. This can have the same adverse effect, for the same reason.
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Yup - Solved 100% :}
And the winners were - in no particular order... (roll of drums) - Bluebird, Craftysod, Stavros and FLJ.
My Solution:
Carefully remove anything with the word AC*MS written on it and blag an old Hitec Ranger2 - 27MHz outfit.
The Result:
Running on the same 4x Dry Cells as the old radio gear -- it works perfectly. Even with the boat so far away I can't actually see it - still perfect - not a single glitch anywhere. ESC works like a charm, Servo smooth and totally glitch free.
Yup, I will get a rechargeable pack - just pleased to get back to the modelling now.
So there you go - many thanks for the input - if nothing else I've learnt there's one particular brand of kit that'll never darken the portals of this boatshed again...
Cheers,
Robin
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Hi there Robin
Glad you have your problem solved, but, sad because you had to acquire a new radio set :((
You have solved the problem :-)) but, like the rest of us - me in particular - some things have to be learnt the hard way - shame but there ya go :o
If you had lived just round the corner, could have loaned you a radio set to try out. Just for info another radio set which to have behaved 'iffy' for me - it the Sanwa Conquest at 40 mghz. It's an 'old' radio set - but by hey it's given me some heartache. The only I reason I used it, is because it's sentimental -bought it from a good shop when I was on my holidays first multi-channel 40 mghz I ever purchased - the rest is history and hard learned lessons <*< <*< <*< late nights, no hair springs to mind.
AYE
John