Weird behavior from a Mamba Monster 2

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I have been running my Savage truck equipped with a Mamba Monster 2 ESC and 2200kV motor (purchased as a combo from Tower Hobbies) for about six weeks and have had no problems with the motor or controller until today.

Less than 5 minutes into my first pack (4S) the truck suddenly went dead. There was no power coming from the internal BEC and the controller itself was showing no lights.

All battery connections were secure, as were all connections to the receiver. Both 2S packs were still showing a full charge.

I noticed that if I turned the power switch off and then on, the ESC's green light and the receiver's power light would come on only for an instant before going dead again. The motor would also begin its startup beep, but would cut off at the same time as the lights. Each time I turned the switch on, it would start up for a fraction of a second and then shut down.

Saddened, I brought the truck back home. When I connected the batteries again on my workbench I verified that the ESC was still not working.

Here's where it gets interesting. On a whim, I decided to see if my Castle Link adapter could still talk to the ESC. I launched the Castle Link software, plugged in the ESC, and it worked! The computer was able to recognize a Mamba Monster 2 controller and read its settings.

After disconnecting the ESC from the Castle Link adapter and plugging everything back into the truck's receiver, I connected the LiPo packs one more time... and the truck fired right up! Throttle and steering commands seem to work perfectly, and everything seems to be back to normal.

What exactly happened here? Is my ESC defective? If this happens again, how can I get the ESC to "snap out of it" without bringing it all the way home to my computer?

 

[X]

Is there a possibility that the switch is intermittent? It could be mechanical, or there could be corrosion on the contacts due to water ingress. You could use a multimeter to verify continuity across it while opening and shutting it, moving it around.

 

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When I had the truck on the bench I cut the switch out and just touched the wires together with similar results. Now the truck is working again, but I've got no switch!

 

[Rooky]

Not having a switch is perfectly fine. And from what I understand, doesn't even void the Castle warranty.

 

[X]

Easy enough to solder one back in if you want it. Could even upgrade and get a more robust switch that is water resistant.

 

[hpicelery]

That's what I'll do if I ever get this problem figured out.

I took the truck out again today, and it cut out on me a couple more times. This time, the truck seemed to be able to recover after sitting for a few seconds, though sometimes it would cut out again the instant I tried to give it throttle. This would only happen after it took a slight knock, like landing a bit nose down off a jump. I suspect that something is loose inside the ESC itself, because I have checked and rechecked all of the external connections.

 

[X]

Easy enough to check for loose items. If you have a magnifier take a look inside. Look particularly for ring cracks around through hole components.

 

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Can I do that without voiding the warranty? I've sent an email to Castle Creations asking what to do about my problem, but I haven't heard back yet.

 

[Rooky]

Can you do which without voiding warranty?

Be patient, Castle WILL respond, it may take a couple to a few days. The customer service over there is top notch.

 

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Sorry, I was referring to the suggestion that I inspect the PCB. I work on electronics for a living so I'm confident I could handle it, but if opening it up would void the warranty then I'd rather just wait to hear from Castle.

As far as being patient... Unfortunately the same inner kid that makes me love RCs has trouble being patient sometimes

 

[Rooky]

I know that feeling ALL too well! Ha!

 

[hpicelery]

The good news is that for the most part the truck is working, so I can still enjoy it while I wait to hear from Castle. I suppose I'll update when I do hear from them, in case anyone is curious.

 

[Rooky]

Please do!

 

[X]

Sorry, I was referring to the suggestion that I inspect the PCB. I work on electronics for a living so I'm confident I could handle it, but if opening it up would void the warranty then I'd rather just wait to hear from Castle.

As far as being patient... Unfortunately the same inner kid that makes me love RCs has trouble being patient sometimes

A fellow electronics guy huh? What do you do? I'm in Electrical R@D myself.

If you are in warranty, leave it. They won't touch it if they feel you have been tampering with it.

 

[hpicelery]

@X, I design PCBs and write micro controller code for special applications. I also build and test the prototypes.

As an aside, I used the tools of the trade to create a cool LED setup for my 1:1 car, but that isn't installed yet. If you're interested I can PM some pictures of it once it's done.

 

[X]

@X, I design PCBs and write micro controller code for special applications. I also build and test the prototypes.

As an aside, I used the tools of the trade to create a cool LED setup for my 1:1 car, but that isn't installed yet. If you're interested I can PM some pictures of it once it's done.

Seems you and I have alot in common. Feel free to PM me that when you get it done.

 

[hpicelery]

Castle has spoken! I forgot to mention in my email to them that I had already removed the switch, so their first suggestion was to try that. After fully explaining what happened, they basically said "gosh that's weird, send it in." Kinda what I was afraid of, but oh well.

My first field repair was just to strip the switch wires and twist them together with some tape. The truck mostly ran fine after that, but it still cut out a handful of times. After that I properly soldered the wires together and I haven't experienced any issues since. I'm still not convinced that the switch was the problem, though, because of the way it would die when I was touching the bare wires together after removing the switch.

I was considering running it for a while longer to see if the problem is gone before I send it in, but with the truck already down for suspension and diff work now is as good of a time as any to send it off.