Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: Klunk on March 30, 2016, 06:34:39 pm

Title: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 06:34:39 pm
After taking all the water out and replacing the damaged wooden areas im having electrical problems.
basic setup is
orange receiver
hi tec 785 hb drum servo
metal gear tower servo (rudder)
6v 4.5 amp battery


problems
Starting with nothing other than power to the receiver (eliminating problems as I connect)
1. when switching on all is ok
2. attach drum servo all  ok, no jittering
3. attach rudder servo, receiver blinks rapidly and servo judders. Drum servo still ok.
4. the ESC for the motor is not connected via the TAMIYA plug but is working (god knows how!!)


Any ideas what I have done wrong!!!
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: inertia on March 30, 2016, 06:57:44 pm
Does the rudder servo have the word "digital" on the label?
I'm still trying to get my head around your wiring diagram... :o

No - it makes little sense. How many batteries do you have in that model? Your diagram implies two......or maybe it doesn't....
What type of ESC is in there?

 Dave M
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 07:03:35 pm
no its not a digital servo dave
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 07:05:12 pm
ps this was the electrics how they were but worked before. im not sure i put it back together correctly!
if you feel a new wiring syustem is needed then im open to suggestions

Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: inertia on March 30, 2016, 07:07:53 pm
ESC type, Motor voltage, Rx type and Rudder servo make and model, please.
DM
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 07:13:21 pm
esc fusion aquacraft 280
hitec 785hb drum servo
tower pro metal gear 995 servo
spektrum dx6i tx
orange 915 rx
motor 400 size motor geared to prop
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: HMS Invisible on March 30, 2016, 07:19:28 pm
4. the ESC for the motor is not connected via the TAMIYA plug but is working (god knows how!!)

The power is coming from the servo cable and through an esc bec component. It passes through a bec diode and likely be destroyed if you persist.

I've had water in a servo. It jitters when it has dried out. No mystery there. :((
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 07:25:29 pm
The esc is only connected through the receiver wires. The tamiya plugs were never plugged in. That's why I don't jnderstand how the esc is working!
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: HMS Invisible on March 30, 2016, 07:54:54 pm
The aquacraft esc bec component lacks "mirror image protection" so the power bleeds through its bec from the receiver supply.
  DM and myself opted for the higher spec, higher priced LM2940 which will not give the same symptom. More importantly, it will not be destroyed if you connect a receiver pack without disabling the bec, either by pulling a jumper or removing the red on the servo plug.

  Refer to the appended image. Without the leftmost 1N4002 the 7805 regulator can feed 4v to the 12v side if you remove 12v then connect a receiver battery to the 5v, as you are doing. As an aside, the second 1N4002 provides an alternative path to protect the 7805, during discharge, if an external 2,000 microfarad cap buffers the 5volt line.

  I have not had time to ask the author for permission to use his image. I'll delete and later upload my own if the objects.
Browse his site if you are curious.http://www.williamson-labs.com/480_dec.htm (http://www.williamson-labs.com/480_dec.htm)
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 08:03:41 pm
That makes sense actually and was exactly what i was thinking but thought better of airing an assumption without the technical back up. Mike i do have 3 spare microgyro 40 amp speed controllers but it is a total waste to put them on this yacht. I would rather not have the motor!4


On the same note I have a 10 amp action speed controller somewhere as well I believe! and 2 electronise as well as 2  gold hi tec esc's. None of which im prepeared to put in this Yacht. How about I disconnect the positve lead from the Esc's receiver and connect the Esc via the Tamiya plug?
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: HMS Invisible on March 30, 2016, 08:19:45 pm
Mike i do have 3 spare microgyro 40 amp speed controllers but it is a total waste to put them on this yacht.
Lucky you! I agree.
How about I disconnect the positve lead from the Esc's receiver and connect the Esc via the Tamiya plug?
Yes, do that.
My mind may be playing tricks but I think you partook in a previous discussion where positve lead disconnection was advised in the strongest possible terms.
The Aquacraft esc may be waterproof but I would use a fuse after a dunking.
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 08:31:26 pm
yes we did discuss removing the red lead while using a receiver pack. i dont have a receiver pack and didnt realise that the receiver could power the esc via reverse electrics via the receiver throttle control lead!
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on March 30, 2016, 08:46:23 pm
just looked at the tower pro servo 995 and it is digital!!

Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: malcolmfrary on April 01, 2016, 09:25:07 am
Quote
3. attach rudder servo, receiver blinks rapidly and servo judders. Drum servo still ok.
1st reaction, try a different servo since that seems to be the point where it goes astray.


Without a reference to the first part of the story I'm guessing that the innards have been wet?  If so, odd bits of wiring might have failed and there might well be more than one problem - "black wire", corrosion on or around terminals etc.  One common failing is that a ground return (sometimes labelled -ve) might be broken, and power that should be going via a big thick wire is now passing through another, much thinner, wire.  The system appears to work until too much current is passed through the thin wire.  Mother nature makes terrible components and circuits.
A re-draw of the wiring diagram using standard symbols would be helpful - it is hard to tell whether the power consists of a single battery connected -ve to ground and +ve supply, or ground somewhere with both a -ve and +ve battery or whether there is just one battery with a lot of connections or a bunch of batteries.
Title: Re: ATLANTIS YACHT - ELECTRICAL FAULT
Post by: Klunk on April 01, 2016, 09:07:35 pm
After 2 days of checking, rechecking, rewiring I have found the problem. So simple as well........One of the cells on the battery was dropping out!
What got confusing was the simple fact that the rudder servo was agitating whenever it wanted. Yes the receiver was flashing indicating loss of signal but I was ignoring that as it was the rudder servo causing the problem which drew a small ampage than the drum servo! Moral of this don't become fixated on what you think is going on. Look at the whole problem and all the symptoms.
Thanks to mine at microgyros and dave from action for their inputs!