complete novice

[jimbo68Participant @jimbo68]

hi all,

have come on here because I bought a Bait Boat for my carp fishing a couple of weeks ago.  It has been built by hand using an Acoms transmitter, servo, receiver and speed controller. It has a motor and rudder (obvious I know) and that is it really.

I am keen to understand how it all works so that i can fix it if it goes wrong – which it already has .

I have a Powertech ‘fully automatic’ charger. Would somebody tell me why I get a flashing light on it after only a minute or so of charging. I thought this meant it had switched to a trickle charge – but after only a minute ???

Also, would trying to run the boat with nearly dead batteries cause any sort of malfuncton? i.e. the motor rotating continuosly when it is switched on ?

Any help greatly appreciated.

[Peter NordsjoeParticipant @peternordsjoe33686]

Hi Jim,

Do you have an electric speed controller or the manual kind?

MSCs use a triple-tapped, high wattage wirewound resistor, which a servo-activated wiper-arm arrangement can put in series with the motor. If the arm is not centered then it would cause the motor to run when you turn it on. Try playing with the trim while lookling at the MSC to see what happens. I found some text on http://www.dansdata.com/ta04.htm. It is about RC cars but the principle is the same and might give you some more insight.

If you have an ESC then somebody else here will probably give you a tip eventually.

As regards the charger I’m afraid I can help you.

[jimbo68Participant @jimbo68]

Hi Peter, thanx for the response.

The speed controller is the manual kind I think, it is an Acoms AFR15.  When I switch the boat on it makes 3 clicks and the light on it goes on and off with the clicks. The Handset is operating the speed controller as it would normally. It will switch from forward to reverse but the motor doesn’t switch off.

I have had a look at the link and I think your’e right Peter, it is an MSC. The arm musn’t be centred properly because there is a curent causing it to turn the motor in the off position. Can you be of any further assistance in rectifying this ?????

[jimbo68Participant @jimbo68]

Correction, just found out is a High Frequency PWM Electronic Speed Controller,

whatever that is……….

[Mike DavidsonParticipant @mikedavidson22772]

     

                     Hi Guys I was interested reading your efforts to fathom out (pun) the speed controller Well, I might be able to throw a little light on the subject for youYou may have read that I started radio control a long time ago with a one valve one channel radio driving an escapement  to move the rudder. As things progressed technologically, along came the wonderful digital proportional system. This was a bunch of channels that you could assign to any function you wanted to work at a distance, speed, rudder etcetera

The channel was what was dedicated to the function like speed, and if you were a radio mechanic like me, you could attach an oscilloscope to the servo input, and see just how those clever japanese were able to do what we wanted, that is that the individual pulse that went to your servo was about one and a half milliseconds long. when you altered the control the pulse width altered from one and a half to two and a half milliseconds wide, and then, surprise surprise, If you moved the control in the other direction,the pulse width altered to one half a milliseconds. The internal logic of the ESC will be set to alter the analogue output to reflect the Pulse Width transmitted according to the stick position on your transmitter. So Jim if I say that the principal of operation is a Pulse Width Modulation,(PWM)  would a little ray of daylight penetrate the gloom? If I accept that I have told you sufficient so far, I guess you can work the rest out> If anybody else would like a bit of explanation, on any aspect, please feel free to ask me and I will be happy to punch a few keys to help

Uncle Mike D.

[Mike DavidsonParticipant @mikedavidson22772]

  Hi Jim , I ‘ve just read a bit more of your problem page, and if you read the previous bit from me, I will try to explain why your motor burbles on slowly all the time Your sticks are sprung loaded to revert back to the zero position if you let go of every thing, and the transmitter has little trim levers on the sticks to enable you to set up a hands free straight running set up if the trim lever on your speed control had a little correction applied, it would be seen by the ESC as a dead slow ahead command. Y ou did give me some good news, when you said that the reverse function worked which means that the ESC was seeing the pulse width going below one and a half milliseconds, which tells me that the transmitter receiver and ESC are all functioning correctly.  So Jim lad get out to that pond with some fully charged batteries, and your diagnostic head on, and go for it……….Mike D

[jimbo68Participant @jimbo68]

Mornin Mike,

thanks for the explanation about the signals and the ESC, I have a feeling your’e trying to tell me the trim needs adjusting but it isn’t that. If I adjust the trim what it does is when it reaches a certain point the motor changes direction.

The motor is running very fast, maybe full throttle. I was assuming that it was a current causing the motor to run when the transmitter is in the off position, then I thought after reading your response maybe it could be a signal but I just don’t know, could it be the transmitter now ? Has the ESC just had it ?

I also forgot to mention (oooops) that this problem started after I had took the boat out and we had a torrential downpour of rain, the ESC isn’t waterproofed in any way and it could have got wet. But if I can fix it it certainly will be from now on.

I have been on the AsTec site and although there is a whole page on spec and set up of the HFR15, there isn’t one in the on-line shop I can buy to replace this one. Do you know of any other make and models I could get to replace it if it is Kaput.

cheers

JIm.

[Peter NordsjoeParticipant @peternordsjoe33686]

Hi Jim,

As I know probably less than you about ESC at this point I just wanted to wish you good luck!

Pete

[jimbo68Participant @jimbo68]

Thanks Pete,

and there was me thinking you were going to give me the answer to all my problems – LOL

Cheers anyway.

[jimbo68Participant @jimbo68]

Come on MIke, where are you ????

Don’t just leave me hangin !!!!!   ( hehehehehe )

[jimbo68Participant @jimbo68]

Incase you’re interested pete and mike, the FET has blown, and maybe the schottky diode, due to a reverse current, probably the water current that was going through it (joke).

I have found some one who thinks he might be able to put it right.

l8trz

[Peter NordsjoeParticipant @peternordsjoe33686]

Good to hear . Expensive stuff to replace.

 Pete

[jimbo68Participant @jimbo68]

hi Peter,

it is the fet that has blown. They’re not expensive really but he has had to order one from the USA so it could be a bit of a wait.

After that it should work ok again. I will make a plastic casing for it, wrap isulation tape round it then smear it all with some sort of grease to keep the water off should any get in again.

[Penny LeeParticipant @pennylee76979]

Jim Crozier wrote (see)

hi Peter,

it is the fet that has blown. They’re not expensive really but he has had to order one from the USA so it could be a bit of a wait.

After that it should work ok again. I will make a plastic casing for it, wrap isulation tape round it then smear it all with some sort of grease to keep the water off should any get in again.

Jim,

I could probably save your friend a lot of bother as my company stocks FET transistors & schottky diodes of all different types,ratings,package pinouts etc.

I can suggest a locally sourced equivalent if you supply a part number or device marking or photograph.I may be able to get a freebie from stock.

Lee Penny

[Mike DavidsonParticipant @mikedavidson22772]

    Ahhhhhhhhh the dreaded Field Effect Transistor, when they were introduced, they were heralded as the answer to all electronic ills, good luck with the repair Jim, take up stamp collecting if you’re bored        Mike   D

[jimbo68Participant @jimbo68]

lol, thanks Mike,

and thanks Lee for your kind offer, he managed to get one from an English company in the end and they arrived yesterday. Maybe it was yours Lee. Could have been spose.

He couldn’t just buy one though, sold them in fives at £7.99 which ain’t bad to get the boat back on the lake considering what it cost me in the first place. He said he had to modify it slightly because the new ones were slighty bigger but "it works superb in his racing car".

Thanks ev1 for your help, I could pick your brains all day Mike.

I do have more things I need to do to the boat which I may need help with but I will post in the relevant forum from now on, I’m a bit new to these forum thingies.

Jim.

[Mike DavidsonParticipant @mikedavidson22772]

Hi Jim, I have given the problem a coat of thinking about, and come up with a batty ideathat your stick may be mounted in the transmitter case incorrectly giving it a permanent offset, or maybe the variable resistor which is part of the circuit generating the control pulse. As you wag your stick about, is the speed controller varying the speed of the motor ?can you identify a null around the mid-point of travel?

If you can identify a null, and the motor stops just before that point, I don’t see a transmitter snag If the motor goes into reverse just after the null, all is well,cos that’s what it’s supposed to do. The speed controller may have a different logic set-up, look for funny identifiers in the part number, then look into the makers literature, you never know, you might have a special unknowingly.  I have come across situations where the potentiometer in the stick mechanism is bigger than it needs to be,and there has been travel left at the end of the control movement, have a look at the stick from inside with your bright eyes on and see if you can spot the mouse in the wheatsack. I wish I had your unit on my workbench, as this sounds like a very good snag to work onand it is more difficult if you can’t see it

Good luck old chum keep pluggin on keep the feedback coming,  somebody will suss it out for you

  Mike   D

[jimbo68Participant @jimbo68]

Thanks for that Mike,

look up there, He’s fixed it. lol – You must keep up m8.

[Mike DavidsonParticipant @mikedavidson22772]

  JIM  I’ve had a little chat with the good folks at powertech,and they firmly deny ever having produced an automatic battery charger like the one you described sorry old pal, it sounds like somebody needs to check each component individually, and shake down anything that looks dodgy. I have been rummaging amongst my pile of circuit diagrams for an article I took from an electronics magazine for a processor controlled charger that is selectablefor 1,2,3,4,5,6,7or8cells and 2,48 or 16 hours charge, but because it was designed for Ni-cadsit automatically discharges the cells first through a couple of FET’s and some meaty wirewound resistors, I use nothing else except  aaa NiMH cells which have a dedicated charger that I bought in Tandy those are the cells I use for my radio and servo’s.   I also useC size Ni-MH for my motor drive, I use six in series to give me 7.2 voltsat 3000mA/H. I have yet to put that boat in the water, so I am conteplating brushless motors and maybe LiPo cells to drive them in case I need a bit more beef to provide a more realistic scale speed. My previous boat an Arun class lifeboat was pretty good for that side of thingsas I used two 540 motors geared down about 5 to oneand D size Ni-cadsat 12 volts 4000 mA/H. I made my own speed controller for that using a servo driven potentiometer driving    a regulated voltage into four 2N3055 H transistors in parallelstraight to the motors,and I don’t remember anything getting hot. If anyone wants the circuit of that,I will attach it to an e-mail no problem .Sorry about the battery charger news

[jimbo68Participant @jimbo68]

mornin Mike, Its a Powertech fully automatic battery charger, model BC6500, I can’t find any info on it but it’s exactly the same as the 6v SLA battery charger that Maplins have on their site. (exactly the same spec)

[Penny LeeParticipant @pennylee76979]

jimbo68 wrote (see)

I have a Powertech ‘fully automatic’ charger. Would somebody tell me why I get a flashing light on it after only a minute or so of charging. I thought this meant it had switched to a trickle charge – but after only a minute ???

My mate Tom(60 watt) is the guy to ask

jimbo68 wrote (see)

Also, would trying to run the boat with nearly dead batteries cause any sort of malfuncton? i.e. the motor rotating continuosly when it is switched on ?

A possibility.

Did you perhaps use 6 volts for the motor with no other battery?

Does your speed control read the transmitter at switch on and set that as the neutral?

Then acknowledge by clicking and flashing ?

Move the throttle a touch and repeat the process to confirm.

Would drive the older brigade nuts when their boat "resets" its neutralin the middle of the pond!

Lee Penny

[jimbo68Participant @jimbo68]

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