HELP!!! DEX410 electrical problems

[dasbo]

Hi folks,

I am having a hell of a time with the electrics in my Durango at the moment. I have an intermittent fault which is causing me a lot of DNF results.

Basically, my car will cut out without warning and I will lose all power, even steering. On picking the car up, I notice that the speedo power light is on, but the receiver light is not. If left on, it will come back to life after anything from 20 seconds to 20 minutes. Its got so bad that I recently had to borrow another car to be able to compete at a local meeting.

Over the course of the last 3 months I have tried combinations of two 6.5 motors (one brand new), three speedos (Nosram Pearl ITSC - brand new, my spare LRP SPX super reverse and LRP SPX Stock Spec from my TC) and two receivers (Futaba 603FF and 603FS from my TC). I have also made sure the connectors which plug into the receiver are on properly, and that the motor sensor lead has been replaced. The only thing I havent changed is my Futaba 2.4Ghz transmitter and Demon lipos.

I thought I had it cracked after having more than a dozen 5 minute test runs last week (after installing my LRP Stoc Spec speedo from my TC) but unfortunately it happened again this weekend. My temperatures after a 5 minute run (checked everytime) are well within limits so it cant be a thermal shutdown. I am not a complete novice but this has got me stumped.

Has anyone got any ideas, as its getting to the stage where I'm seriously thinking of giving up offroad, even though I prefer it to TC, and love the car.

[Northy]

What track surface do you race on?
Does it do it as you hit the face of a jump?
Does it do it as you land from a jump?
Does it do it at random points on the track?

G

[JohnM]

It's not something really silly like a dodgy link wire between the LiPos is it? I've had some gip with mine (crap soldering skills).

[dasbo]

Hi Northy,

Thats a blistering quick response.

Its run on a grass track (and garden) and will happen on a flat section without any jumps, so I'd say its random, which is why its so frustrating.

Cheers,

[Bungleaio]

I doubt it is the lipos as they are just a power source, if the speedo light is on then the power is flowing.

It could be the transmitter becoming unbound or not sending a signal out to the reciever hence the light going off. does the transmitter have the same issue with your TC?

Also check the aerial position, mine is very close to the main battery cables and the car would cut out occasionally, I pulled some more wire through so it was coming out of the top of the tube and it seems to have cured it.

[Northy]

My first thought was static if it did it on the face of a jump on a carpet or astroturf track

So... other than a bad connection, not sure now. Could even be a bad connection INSIDE the lipo, so worth trying a different one if you can borrow one?

G

[DCM]

have you checked the temp of your receiver?

[wes]

Sounds like you could have a battery problem/battery wiring fault, with the weight of geared diifs in a Durango they pull a huge amount of amps under acceration if it draws the battery under 6 volts it will cut in the lipo cut off on your speedo/receiver failsafe.

[DanB4]

I reckon it's a receiver problem Dasbo......

[fastinfastout]

it looks like your receiver is un-binding. Try a capacitor on your receiver, spektrum sell them and they plug into a spare channel. Use a Y connector if you dont have spare channel on receiver.

[Matt Airbrushing]

Spectrum can also be affected by static.

I also fly helicopters and this can be a common problem.

Earthing the negative side of your battery to your chassis should fix it (although working out the source of the static would be a better idea)

[dasbo]

Thanks for the response guys.

I'm going to try and borrow a capacitor for the receiver and see if this helps. After that, I'll check the other stuff mentioned above.

Thanks again.

[IceMike]

could be as simple as a break in ya link wire between receiver and speedo. check the connections there.

[mpg200]

Ok here's another angle,
what about the steering servo, it seems to be the only thing you havnt changed. If it has a wobbly it could cause excessive current drain from the receiver (source of its power) and cause the reciver to over heat and or shut down for a while. I was testing servos last night to find a savox can pull nearly an amp at full steering lock.. I had to run down end points to stop servo stalling. still get full steering but now only about 600mA at full lock

[reg]

it might also be putting the fail safe on due to noise from the steering servo,iv had to move my speedo wire as far away from the servo(SAVOX) because of this,when i turned the steering quickly it made the speedo glitch,the blue full speed light would flicker on and off and the car would jump forward,i found out it was the buzzing noise because it would do it when i tried to turn the wheels by hand as this made it buzz more,after moving the speedo wire away from the steering servo it stopped,as i moved it closer it did it again,

[annonymous]

i had a very similar problem in my DEX -

are you using bullet connectors? if so, check to see if they are tight in the terminal and the springy part of the connector that provides the holding pressure isn't loose.

My car was doing everything weird because of this

[dasbo]

Another couple of ideas for me to try. Cheers guys.

My power wires are currently soldered to the underneath of the tabs on my LRP speedo and are as far away from the receiver and servo as can possibly be. But of course, you all know how tight things are in there so nothing is ever "far away". My servo cable is currently routed near the end of the motor so I'll try shifting this to the other side too. I never thought of changing the servo itself, so I'll have a go with that. My speedo is soldered to the motor so no connectors there, and I replaced my connector ends at the lipo end with fresh ones too and always make sure they are screwed tight.

Fingers crossed one of the above will sort it out.

[fifi]

Someone had some similar issu.
The steering linkage was overtighten.( part 340001).
The servo was asking too much amp the receiver or speedo cut off.

[HarlowS]

I still reckon it could be with the Spektrum, can you access a spare tx and rx ?? Maybe just a cheap one ??

[dasbo]

Hi folks,

Its been a while due to holidays and work, but I finally got the chance to see if a new servo (with the cable routed opposite side from the motor) and capacitor plugged into the receiver would fix my "glitch". Unfortunately, it did not.

I had a short practice run before the first heat and so far so good. However, in the heat itself, it died after the second corner so I never even managed a lap. I went home straight after. What makes it worse is that I did a full rebuild on it before this weekend and the car was handling great. I have never had this much problems with my electrics in all of my RC hobbying years and just cant figure it out.

I will try a couple of more things before I give up. Feel free to fire more ideas.

PS. After getting home and removing all the electrics to "bench test", I plugged my Nosram ESC into an old lipo the wrong way round, shorting it out. I guess I wont be using that speedo again. Can things get any worse? Bah Humbug!