Another Dead Mamba Max?

[b0x]

I was out running today and my truck broke, yet again. Everything was fine for about 10 mins, then it just started jerking and wouldnt go anywhere. Its like it tries to go, but doesnt have enough power. When I pick it up and hit the throttle it works fine. There is no bind in the drivetrain. The lights on the esc are like they should be. I havent taken anything apart yet to get a close look, but everything looks fine on the surface. The diffs and driveshafts and spur/pinion look good.

Seems to me it has to be the ESC. The only other thing I can think of (since someone else ran into it, merc maybe?, dont know what his symptoms were), but could it be a broken motor lead? Again, I havent had time to take it apart yet, just wanted to get your thoughts.

[BitHed]

...Are you running a UBEC?

[b0x]

Yes. It never glitched before, unless it was out of range, and when it would first start up... when it all worked, when I accelerated from a stop it would jerk maybe 1 time then be fine once it was rolling, and never had any problem starting up like it does now.

I forgot to mention before that if I pushed it with my foot to get it started it would be fine until it stopped, then couldnt get going again.

[mbarker]

Mine does the same thing.

[b0x]

No one else has any thoughts?

[rrlc]

Try progamming more starting power into the mamba max. Or using a smaller pinion might help.

[terminator fan]

try another batteries, could be your batteries are not holding its charge

[b0x]

I charged up the batts again and I still had the problem. However, I know they have a proper charge since when I run it with the wheels off the ground they go full speed. I will try reprogramming the MM, but since this changed after it was originally working for awhle makes me worry...

Update: I tried changing all the settings, like punch and start power, it didnt help, but in the very little bit I tried to get it to work, probably less than 1 minute of throttle, the ESC got VERY hot as did the wires to the motor and the batteries (the batteries were room temp).

[Kostaktinos_mt]

seems like a bad figure to me...
are you absolutely sure the motor-to-esc wires are intact ? and perfectly soldered? maybe a loose/broken lead?

[b0x]

No, that is the only thing I am NOT sure about. I am going to take it apart today and check it out.

[Kostaktinos_mt]

ok...let us know...
the way you describe it [especially with the esc getting hot] and combined with the starting problems, it seems like it...[one of the three phases is loose]...

[b0x]

Ok, I had lost the black wire on the ubec, but even soldering it back on didnt solve the problem. It gets VERY hot very fast, much hotter than its EVER been. The motor leads are fine as are the solders. Time to send it in?

Also, what do you mean when you say "looks like a bad figure" and "one of the three phases is loose"?

[Kostaktinos_mt]

'bad figure' = sort of 'bad news' or 'not normal'... sometimes, i just spontaneously translate my first language lingos to english, and the results aren`t always understandable... :o

one of the three phases [each motor wire represents a phase inside the stator of the motor] has gone loose = one of the three phases/wires doesn`t get proper commutation = its loose, makes bad contact or the esc is shot...

i guess you could remove completely the motor from the truck and check if its wires are stiff and hardly bend-able as they are supposed to be...or if there is something broken inside them... just a thought before hard maintenance [=send the thing to castle]...

[Kostaktinos_mt]

alternatively, unsolder the bl motor, solder a brushed motor to the esc [per the mamba instructions], set the esc for brushed mode application, and test it... that would show if the esc is damaged or if its just an esc-to-bl-motor problem or a bl-motor-problem solely...

[themerc64]

b0x,
I still cant get over those Feigao motor leads:rolleyes: Dan at Kershaw Designs wanted me to send mine back to him so he could try replacing the leads. I forwarded Kostas' and my thoughts about that to Dan and I haven't heard a word from him yet. Dan probably doesn't want to replace the motor and I really dont want it back:rolleyes: I would rather have the credit to get something else. I also just got my MM back from Joe at Castle and they still have no idea why some MM's work on 14 cells while others dont:rolleyes: or just dont want to tell us:rolleyes: They refurbished and tested mine and sent it back. I guess since I am still trying to sell my E-Savage I will put the MM up for sale too. I already sold the Quark 125B I had bought...

[b0x]

all i have is a 17t motor for like an rc10... I guess on just 7 cells I wont murder anything? I could try with that, but it may not have enough torque if it was working perfectly, so I dunno. I will try to send joe an email and see what he thinks.

[Kostaktinos_mt]

yeah you can try with a 7cell pack...
and install the thing on a light vehicle if you have any...
just don`t even dare to run a single 540 brushed motor in the esavage; it will fry in a minute...
if you don`t have any other vehicle, or any 550 motors [stock ones?], just run the motor alone without any load and check for the temps of the esc... if the esc is damaged, it should get warm or hot even with a healthy brushed motor with no load on it...

[b0x]

I sold the stock esc/motors :)

I do have another lighter vehicle, just not here... so I guess my only option is to run it with no load and check temps. Will update....

[themerc64]

Well Guys,
I thought you might be interested in how Dan at Kershaw Designs attempted to warranty my Feigao motor with the broken lead. Needless to say it runs as bad as it looks. I would not expect anyone to run with an abortion like this. Way to go Hack Master Dan!

[Kostaktinos_mt]

three words: 'parasitic resistance paradise'...

[veedubrob]

When I first put one mamba in my truck it burned up the esc pretty fast. We were running a set of cells to it that is two packs were powering it. That could have been the problem so I went back to a two motor system with the two mambas and havent had a problem since.

[b0x]

It ran fine for 10+ packs veedubrob, so I dont think what you said has anything to do with it.

KOSTA: I put my 540 motor on it with 7 cells, and ran it awhile. Got the motor to get pretty hot, which I expected, but the ESC didnt change one little bit. When I put the feigao back on (I checked the motor leads, all perfectly intact), it did the same thing it did before, all jerky and glitchy until it gets going, then its fine. Its also fine with the wheels off the ground. Both the esc and motor got hot again, but not as hot, although I didnt run it hard. So it seems to me that it is the motor? I dont really know, I wish I had a place to take it to that actually knew about high powered brushless trucks. I may give my local hobby towns a call to see if they have anyone that knows what they are talking about. Anyway, tell me what you guys think. Does feigao have any sort of repair system? What about a mfg warranty? Give me any info you can...

[themerc64]

I thought I would let you guys know that Dan at Kershaw stepped up and resolved my Feigao troubles. There must not be much, if any warranty support from Feigao. I guess it is up to you to buy them from a retailer that is willing to bite it when the Feigao bites it. Dan sent me what I wanted... a dual 700 conversion kit. I still dont want to play with this thing and it is still up for sale.