Couple of issues wih my Mamba Max - RC-Monster Forums

rchippie · **Couple of issues wih my Mamba Max -** 01.19.2007, 09:38 PM

#1
I've had my MM for about 2 months. I've had the following problem sinice i got it. After a little bit of running my MM will stop working all together, then after a couple of seconds start up again. I'm using a UBEC with 14 cells & a 7XL with a 13/46 gearing in my MBX5.

#2
It thermaled for the first time today after only 5-6 minutes of running at the most. My fan broke so the temp reading was 200 using a ofna temp gun. I normally was using a 5 volt fan getting power from the reciver worked fine. Then i switched too a 12v fan getting power friom te speedo the part of the fan with the blades popped off last week & i popped it back on. Bu today it stopped working altogether. The temps outside were great less the 80 degrees & the body was vented very well . Do you guys think the gearing or the fan not working is the reason for the thermal shut down ?. My gearing is a 13/46 with a 7XL on 14 cells.

BrianG · 01.19.2007, 09:53 PM

That gearing doesn't sound unreasonably high. I wonder why it's getting so hot?? What do you have your MM settings at? I would lower the timing and lower the starting power to help ease up on the controller a bit. What is the temp on the motor and batts?

rchippie · 10:21 PM

I think the fan breaking was a factor. As for motor i forgot to check.

What do you think about the speedo cutting off after a little bit of running. I think it has to do with the UBEC because i had no steering when it cut off. Then maybe 3-4 seconds max it would start back up & run for a while.

BrianG · 01.19.2007, 10:32 PM

Well, if your BEC is cutting out for whatever reason, it will affect steering and throttle. The ESC gets the throttle signal from the receiver and if the receiver loses power, then there goes the signal. Who knows, the BEC could have a bad solder joint, not rated for the current the servo and fan needs, etc. You can always try a receiver pack to verify that it's the BEC.

rchippie · 10:48 PM

I plan on trying a reciver pack on my next outing When i had my BL mbx4 i used a reciver pack with no issues. I'm hoping the UBEC is the reaon for it cutting out.

Also i just reprogramed my speedo. I lowerd the timing from normal to LOW & start power to low.

BrianG · 01.19.2007, 10:46 PM

What BEC are you using? Sometimes a properly sized capacitor can help a lot to even out the bec voltage, smooth out current pulses, and filters any noise from the bec output...

rchippie · 01.19.2007, 10:50 PM

Im using a UBEC that i bought from mike.

BrianG · 01.19.2007, 10:54 PM

It's kinda rare, but I've heard a couple people have a problem with them. Could be a loose solder joint or something equally simple.

coolhandcountry · 01.19.2007, 11:01 PM

It sounds like a ubec prob.

rchippie · 01.19.2007, 11:16 PM

Quote:

Originally Posted by coolhandcountry

It sounds like a ubec prob.

I hope thats the problem leroy . Brian thank's for your repliys.

GorillaMaxx360 · 01.20.2007, 12:50 AM

yeah hopfully the bec a lot easer do deal with.

BrianG · 01.20.2007, 12:56 AM

Yeah, I hope it's the BEC too. Good luck, and let us know what it turned out to be.

Serum · 01.20.2007, 04:50 AM

Hippie; You did removed the red wire from the ESC, right?
Seems to me like the UBEC is loosing signal.. Either that, or the receiver is not working properly. That thermalling you had last time is result of the fan going off-line, but IMO it should run longer without a fan. It can be the timing indeed. Sometimes a softer timing makes the motor hotter than it was.. (noticed this with my schulze/plettenberg setup) if i recall this correct; a 2 pole (hacker) needed a harder timing than the 4 pole plettenberg.

01.20.2007, 10:41 AM

I would think if its the UBEC, the truck will be freaking out and cogging badly as well. That usually goes hand in hand. The fan breaking will do it also, its holding the dead air on the controller. No fan is much better than a poor fan or broken fan.

Serum · 01.20.2007, 10:59 AM

It's not that a fan isolates a heatsink. it's not helping the airflow, i agree.

A ubec can just drop out, it's not said it's stuttering, it's just stopping. A ubec with a thermal problem or such, might just loose it's power. Not necessarily causing a stuttering/cogging problem.

It's quite simple; if it's not the UBEC, it must be an error in the receiver. Steering doesn't work, truck won't move.. First thing I suspect is the UBEC. If you have got an external pack, test it.. If it still does the same; replace the receiver.