mamba max pro problem
 

ok heres the thing , i have noticed when using my mmp on a hightec 5955tg or 7955tg when you turn the wheel alot it will glitch and some times the motor will turn on and the servo just stops , ive tryed to run it on 5.5v-7.v and still the same thing , also had a guy runnin one here at the track also and it did the same thing , one more thing my fan allready stoped working i was runnin it on a 6.5 and noticed it seemed like some thing was wrong , i pulled it off the track and temped the ESC and it was at 210 never did get the fan to work , is it posable to send in just the fan ? thx joe

Are you running a 2.4GHz radio? It could be interference from the metal gears if you aren't. Otherwise there may be binding in the steering mechanism causing a BEC overload...though that doesn't really explain the motor movement. :neutral:

yep running 2.4 even did it with just the servo layin there not in the car , just with the arm moving left to right , idk what i could be ive seen it on 2 production mmp now , the beta model i have does not do it

I wonder what's changed between the beta and the production model?

Nothing changed between the Beta and production models...

Joey, have you tried swapping out the RX?

yea it has happend to both of my rx's and my buddy that i race with i will try and make a video and up load it

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The receiver light going out is a clear indication of no/low voltage from the BEC. However, what is causing that? It could be a faulty/weak BEC or maybe there is something wrong with the servo itself.

To eliminate the BEC as the culprit, try a receiver pack or external BEC. If it still has issues, I would suspect the servo.

I had a Hitec servo a while back where one of the internal gear pins had worn away the exle point in the case and elongated the hole. It would run fine sometimes, but then other times would bind up and stall the motor and do exactly as you describe, even with no load like you demonstrated.. Do you have any other servo you could try?

i have had the problem before, turned out to be the servo, i would try it with another servo, if it still does it then you have a bad bec

Would setting endpoints on the tx or checking for binding in the steering links help?

I have a similar issue with a hitec 985mg. I have the dx3s with telemetry so I can monitor bec voltage on the transmitter. With the power on, the telemetry shows 6.2v, when I start steering, just like in the video shown above, the bec voltage sometimes drops below 4v. This even happens without the wheels attached.

Thing. Is I'm not the only one with this problem some one else at my track had the same problem on his t4 with the mmp on a 7955tg , there is no binding I took it out of the truck and ran the servo by it self and still did it

well guys i got it fixed i went up to the LHS and got a "glitch buster " and works fine now , i guess the pro cant handle big servos :) 6 bucks to fix the problem thats not bad

http://www.horizonhobby.com/Products...ProdID=SPM1600

This looks like the same behavior I've been seeing with the MM Pro.

My setup uses a Pair of MG995 Servos. I blamed it on a bad servo even though I had just installed them both brand new. I then brought it in the house and swapped out the servos.

I haven't had a chance to run it again yet though. Hmmm..........

How many amps is the MM Pro BEC supposed to be good for?

I just did a quick test with various loads with the BEC set for 6v:

5.94v unloaded
5.76v @ 0.48A
5.72v @ 0.64A
5.70v @ 0.95A
5.63v @ 1.87A
4.16v @ 2.77A

Not sure exactly what point the BEC voltage hits its max, but I would say right around 2A. As you can see, the output falls dramatically somewhere around there.

Thanks Brian,

This explains what I witnessed.

A High Torque Servo is likely to draw more amperage than this, especially when fed more than 5 volts. And especially a Pair of High Torque Servos.

Hmmm....... I thought the Internal BEC would be more beefy than this.

Is this a firmware issue? I was running version 1.2, since I read there were motor starting issues with version 1.3.

nope i dont think so i ran 1.24 and still did it , i went back to .22

I wouldn't think firmware would help or hurt the BEC output; that's more of a design consideration. The BEC circuit is actually quite tiny, so it stands to reason the ouput would be what it is.

MMPro V2 already?... :oops:

I don't think it's necessary. The BEC capability is fine IMO for the types of vehicles it was designed for, and the size servo normally found in these vehicles. Making a higher current BEC would require larger components and obviously a larger PCB. If a stronger BEC is needed, it's a simple matter to disable it and run an external one.

I wonder how much the BEC's amp carrying ability is affected by input voltage?

@Brian - What input voltage did you do this testing on?

what I'v knowticed is...

spek RX+ jr 650 servo = RX low volt shutdown
spek RX + 617 bluebird servo= same thing...

BUT!! I'm starting to think that the MMp killed one of my spek RXs, it(RX) worked fine on thu when I used my RX8, but when I switched to the MMp it started to shut down and glitch:cry:

this was in a t4, 2s, 6.5


also the esc hit 120-130 with the fan not turning on...

I'm running a hs985mg in a mini ste. This isn't a high torque servo(172oz-in@6v) and without the wheels on it wouldn't be drawing many amps, but I still see voltage dropping below 4v. I had the bec output set a 6v. I'll lower it to 5.5v and then 5v to see what happens.

edit: just tried the 5.5v setting (dx3s reads 5.7v). with the truck on the floor, after turning the wheels 16 times from left to right, the bec drops below 4v once. did this twice with the exact same result. with the bec set at 6v the voltage would drop below 4v after about 5-6 turns.

I had it hooked to my PS unit, which is 14.75v.

The Spek receiver is pretty solid. I find it hard to believe it is dead. What I have noticed however is that they seem to be pretty sensitive to any noise.

Well, judging from my tests, I bet those servos are pulling over ~2A. It might help to put a capacitor on an unused servo channel, something like 10,000uF which will help provide that extra boosts when current spikes.

I don't have any problems when driving the truck, just the occasional 'beep' from the dx3s when voltage drops below 4v. It's ok for my 4.8lbs mini ste but I also want to use the mmpro in a 7lbs e-maxx.

edit: I'm running 6s

There are several other factors of actual running that will affect these results.

If your tests were quick, the ESC was not up to operating temperature. With the ESC powering a drive motor and carrying an amp load, the BEC circuit temperature will rise just from the heat being given off by the Power board.

What are the results on 6S input voltage?

After signing up to be a Beta Tester for these units, I'm sure several thousand people signed up before me.

In Actual running, it was noticeable, the glitching really didn't set in until after 10 minutes or so. This leads me to believe, temperature affects BEC output.

The "Glitch" would show itself in the form of:

If I were turning, the steering would momentarily stay in that position or the truck would not turn when going straight.

Afterwards, I disconnected the steering and checked for binding. There wasn't any binding.

Interesting...

I have seen on my many travels that for high powered servos, esc manufacturers recommend running an rx pack (of sorts) wired to the servo in series ( I think) via a y-splitter, so that the esc was only really providing the signal to operate the esc, with the rx pack providing the go-juice; rather like having a glitch-buster capacitor plugged into the rx.

Not the most compact or elegant solution, but one of three options along with the cap or running an external BEC..

I find this rather disappointing. For me, a major selling point of the MMPro was the switching BEC good to 6S (though I only planned to use if for 3-4S). If I have to use an external BEC anyway to run a decent power servo I might as well just just an original MM and the BEC (for 3-4S).

(Reminds me of my Havoc 3S, which, on 3S, needed an external BEC to run a good servo.)

I've only run my MMP in 1/10 vehicles with servos that are suitable for said 1/10 vehicle. No problems at all. The MMP is made for 1/10. Usually, 200 oz/in servos are not necessary for 1/10. The MMP is fine in the environment that it was designed for.

the mini ste is 1/12, and the servo I use is <200oz-in.

I would hate to be in Castle's shoes TBH. People want more and more powerful systems in smaller and smaller packages. It has to be a design challenge to do so!

172oz/in at 6 volts is a high torque 1/8 servo - in fact only a scant couple servos with this power were even available just 2 or 3 years ago. 100 oz/in is plenty for a 1/12(and will be much easier on the ESC BEC). That said, I would think the MMP BEC should handle the load of this servo on this small vehicle as long as the servo is working as it should(worn gears will bind and cause high current draw in use, though).
Likewise, and standard linear BEC on a 3s rated ESC will be best served with an external when 3s is used - just the nature of the linear BEC and not specific to the Havoc.
Lets face facts here - the MMP is a 1/10 ESC intended for 1/10 vehicles - many folks here will be using it in their 1/8 buggies - the MMM is the Castle ESC intended for 1/8. The MMP is a cool little ESC, but it is half the MMM in reality and expectations need to be realistic. :)

I just think it's strange this wasn't noticed in beta testing.

edit: just read mike's post. So, I'll drop to 5.5 or even 5v bec output and it should be solved.

so.... back to running external BECs. Great.

The more things change. the more they stay the same. :neutral:

It's not really a "problem", it's the way it was designed. Dropping the voltage will help and adding a capacitor (~10,000uF @ 10V) can also help supplement the BEC under peak loads.

I'd rather limit the load on the bec, so I might just drop to 5v. The 985mg was the smallest servo I had lying around. I forgot I actually used that servo in a Muggy and it did okay. Kind of puts using this servo in the mini ste into perspective...

/sigh

The MMPro BEC is actually just as capable than the MMM BEC, which no one has complained about.

The BEC on the MMPro wasn't designed to run multiple ultra-high-torque servos. It's a 1/10th scale and 1/8 buggy controller.

The current limit is set to about 4.5A on the MMPro BEC, but will fold back if the temps get high. Remember, this is a pretty small integrated BEC.

After my "glitchy" run, I dissected the non-working servo and found it's control board burnt. Even though, it was the first time I ran it, I may have gotten a bad one. I replaced the bad servo, with another MG995.

After turning the BEC down to 5.0 volts, I just took another run. It did not Glitch a single time. Yes, this is running a Pair of MG995 Servos.

I would also like to add, the power delivery of this ESC is really smooth.

This is a light weight, low slung E maxx using a HC 8 Pole 1600kv Heli outrunner geared 14/52 (31 mph). Temps on everything were only slightly warm. The ESC's fan only came on one time during the 30 minute run.

A pair of 6S 26C 2600mah Kong Power Packs in parallel supplied the juice.

As for me, I believe the problems I experienced were to blame on a bad servo.

And they all lived happily ever after... :yipi:

Heres a question then, and a good one at that (rare for me...); just how much torque do you really need to turn the rather small and lightweight wheels of a 1/8 buggy?

I have a pair of 645mgs in my 13lb truck, turning 1lb tires- thats about a total of ~250in/oz of analogue torque ( :P ) turning 2lb of rubber, and it does so pretty well.

Do we really need 200-300in/oz digital servos in 6-8lb buggies, turning tires that weigh... not very much?

In my 8ight I use the JR 9100s which is 180 oz-in of torque, .06 seconds to 60 degrees at 6v. I highly recommend it.