mamba max pro problem

[Metallover]

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

[BrianG]

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.

[suicideneil]

MMPro V2 already?...

[BrianG]

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.

[sikeston34m]

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?

[whitrzac]

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

this was in a t4, 2s, 6.5


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

Originally Posted by BrianG

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.

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.

[BrianG]

Originally Posted by sikeston34m

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?

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

Originally Posted by whitrzac

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

this was in a t4, 2s, 6.5


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

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.

Originally Posted by drkdgglr

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.

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

[ta_man]

Originally Posted by BrianG

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 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.)

[Happywing]

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.