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[BroomBroom]

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

[stallspeed]

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

[John W E]

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

[wideawake]

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

[stallspeed]

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.

[John W E]

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

[BroomBroom]

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

[GG]

Is that coil of wire in the lower LH corner of the photograph the receiver aerial?
If so uncoil it and try again.
GlynnG

[stallspeed]

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)

[FullLeatherJacket]

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

[DARLEK1]

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...

[OMK]

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.

[OMK]

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?

[FullLeatherJacket]

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

[BroomBroom]

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

[FullLeatherJacket]

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

[BroomBroom]

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

[stallspeed]

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.

[craftysod]

It sounds like you have a dodgy servo,swap for another.

[stallspeed]

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.

[funtimefrankie]

Is there a separate battery for the motor or is it ALL powered from the four cells?

[stallspeed]

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.

[craftysod]

If you read the first post .prior to hook up motor and esc servo chatters,something wrong with radio gear,not motor

[stallspeed]

The tiny tick is normal with standard analogue servos.They have a 1⁰ deadband

[BroomBroom]

Eeeekkk!

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