Oh No Not Again!

[Gates Mini Racing]

For the second time, my CH2 on a controller/reciever has busted.[!]

The first was a 27mhz Acomms controller, which was on a car using an MSC, when it got stuck accelerating I managed to lock it into a circle so I could comically run round in circles behind it. [)]

The Second (today) was a 40mhz Futaba, which was working fine. I heared an (eventually unrelated) grinding noise and pulled it over. The wires had got stuck to the can in a molten dripping mess. I unpugged it, yanked out the battery and the ESC to stop it melting too.

After I stuck in a stock silver can to test, I was shocked when the green light came on on the ESC, but didn't work. I tried an unloaded motor, again nothing. Hoping the ESC had not been cooked I choose Ch1 and sure enough the steering can make it accelerate. Yay. So the same problem has happened again. I have a new reciever (planned for my mini arriving)[!] so will see if it is that or the transmittter.

It would seem that I am destined to have only one working controller! []

Am I the only one this has happened too (twice)! []

Any ideas to fix this/comments welcome and really apreciated! []

Many Thanks

Mike

[GPZ1000RX]

How are things getting hot enough to melt wires?, and what things are getting so hot?.

[Gates Mini Racing]

I really dont know how or why it got so hot.

My guess is it is one of two things

A) The wires were all bundled together (although the speed controller wires were bundled to it and were fine.

2) They were touching the bottom of the can. Being an 11T it gets quite hot. Maybe too hot.

Ah well I like the smell of soldering irons anyway...

[Scorchio]

Hi Mike

A long shot here, but were your reciever wires wrapped around your motor wires, I'm assuming an 11 turn is gonna suck up quite a few amps and as a result more RF in the wires interfering with radio gear.

And a longer shot: could your gearing be causing the heat problem?

quote:

Originally posted by Gates Mini Racing

The first was a 27mhz Acomms controller, which was on a car using an MSC, when it got stuck accelerating I managed to lock it into a circle so I could comically run round in circles behind it. [

)]

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id="quote">id="quote">

And thanks to the image this last comment conjured up I have to clean 2 monitors a 'VINTAGE' synthesizer a keyboard and mouse.......I just sprayed them with a mouthfull of tea, thanks mate []

[GPZ1000RX]

Nothing, including the motor, should be getting hot enough to melt anything!

Use quality wire and connectors (NOT Tamiya!) for motor/battery/esc connections and keep it all as short as possible.

No wires, including the motor wires, should be up against the motor can, where they might melt if the motor does overheat.

The radio wires should be kept well away from the motor/battery/esc and their wires.

The RX aerial must be kept as far away from all other electrical things as possible and it must not be shortened or coiled up tightly.

It's not easy in the tight confines of some cars but follow the basics above and keep it all neat, tidy and secure and you shouldn't have any problems.

Two questions arise about your overheating (assuming a Tamiya connector hasn't melted)

An 11T motor MUST be geared very low or it will overheat. (if this isn't possible then don't run it in that car)

If the gearing is OK then a low turn motor MUST be serviced every 10 runs (more frequently if racing), including comm skim and new brushes, if you don't do this it will overheat!

Keep on allowing any motor to get too hot and it will be ruined sooner or later and it may well take other things with it.

Many Tamiyas aren't meant to use such powerful motors and extensive modifications have to be made to do so. They weren't meant to handle the resulting speed either!!!!!!!!

To repeat myself, in most basic Tamiya cars, a 27T stock motor is plenty and they bolt straight in, don't need expensive batts,ESC, different gearing......blady, blady, blady....................blah!!

Hope all this helps.

[Gates Mini Racing]

The car is a TB02, with 20T to 55T gearing and an 11T, with the RX cable tied to the top of the servo as in the instuction pics. The antewnna does brush the top of the heat sink but that is about it...

The pluggs were the standard gold coloured (me thinks brass) on the Ripmax and Mtroniks (yeah a cheapy crappy one) that came as standard on the items, but survived. Just. I think it just melted to the can.

Thanks for your help on that GPZ and(you should see the problems I have with my Mini!)

Scorchio,

It must have been pretty funny, as I had just put a new pack in, and was running after it as I flung down my transmitter and run arms outstreched after it, as the circle became bigger and bigger (it didnt kick out being FF). And shouting/praying/cursing loudly that it wouldnt hit the sides!

Worse still, is a time I drove the same car without the ariel on the controller up, it went to the end of the driveway and up a hill on the main road, with me chasing after it. It was a close shave with some 1:1's that day!

Thanks for your suggestion about interference, this is quite possible, I did have some probs on my mini, but it is doing it whilst the motor is out of the car and im testing it, so it may be a problem with the RX itself which means another £19 or hopefully a new TX (around a tenner).

Cheers and thanks guys for all your help!

Mike

[GPZ1000RX]

Your number one suspect is the connector, change to powerpoles or similar.

No 2 is the gearing, change the pinion for the smallest that will actually mesh properly.

Don't forget the motor maintenance, 11Turns is close to a F1 spec 1/1 scale and they are just about worn out after one one meeting!

A lot of racing guys service their motors before the final qualifier at every race meet, they bring a comm lathe with them for that purpose

So the motor gets its maintenance every 5 runs or about 25mins run time. Fail to do this for couple of meetings and the arcing and current draw go sky high and, if you're lucky, the ESC shuts down before major damage occurs!

[Gates Mini Racing]

ah I didn't know this...

the motor is a cheapy one (unstrippable) and I certainly didnt know that running it into the ground could break my ESC [xx(]

The other motor with which it happened was a Tamiya silver can, also not stippable, but my motors are only used for bashing....

Many thanks for all your help

Mike

[mud4fun]

Hi GMR, I had similar problems the other week. The guys above are quite correct but a couple of other points though:

1) Try and get a matched TX and RX, ie all Acoms or all Futaba, mix and matching doesn't work very well in my experience. Possibly buy yourself a new pair of xtals too. Ideally switch to 40Mhz as there is less interference. I use a cheap futaba attack 40Mhz TX which works well and I buy Futaba RX and servos in my LHS.

2) The Tamiya connectors will cause a problem so I have now switched to powerpoles (or will have when they arrive!)

3) I use a 13t Tamiya Super touring motor, these can be had for about £25 from HK ebay sellers. They have loads of torque which will be better in the 4WD TB02 for bashing. It is a quality unit with internal fan on the rotor and good cooling on the can. I have been using several of them, including one with 9.6v and I've had no problems. They do require brush changes more often but I've put in over 10hrs use on one without needing the comm touched yet. You won't get long run times though, about 8 mins from a 2000 pack and low gearing. Alternatively try a Reedy 19t spec motor (£45) which gives a similar performance generally to most cheap 11-14t units.

4) I've melted the solder on the motor terminals a couple of times, once was when I was testing my group C chassis and I'd way overgeared the motor. It got burning hot. I now use the smallest pinion possible in all the cars I run with modified motors and work up to a bigger pinion once I know it doesn't get hot!