mamba max pro problem

yes i still run the cap , it helps alot it wont shut off anymore :)

[J57ltr]

So Joe, have you checked out your servo?

sikeston34m, Yes you and Joe's friend are the other 2 I was refering to. What was wrong with your servo?

Jeff

[sikeston34m]

Originally Posted by J57ltr

So Joe, have you checked out your servo?

sikeston34m, Yes you and Joe's friend are the other 2 I was refering to. What was wrong with your servo?

Jeff

I believe it was a factory defect. I took the servo apart and it's control board was burnt.

This tells me that I "over amped" the BEC inside the MM Pro, without damaging it.

I also believe the BEC has over amp protection.

As a servo's gears begin to wear, it draws more current. If a person is having problems like this, my advice would be to check your servo.

[J57ltr]

So it was a new or pretty new servo in your case? I am wondering why adding a cap "fixed" Joe's problem.

Jeff

[Pdelcast]

Originally Posted by J57ltr

So it was a new or pretty new servo in your case? I am wondering why adding a cap "fixed" Joe's problem.

Jeff

WARNING: Long boring technical explanation follows:

We've seen the same thing on the bench since this problem was reported. Apparently, some of the JR servos draw peaks (short -term) of several (5-6) amps for a couple milliseconds when changing direction. (We have speculated that the drive transistors in the servo are shooting-through during direction changes, but haven't yet verified that.) It's just barely long enough of a surge to trip the BEC over-current protection in the MMPro, and it shuts off the BEC for about 50ms. Adding a big capacitor to a servo connector (like a stutter-stopper) supplies enough current during those big surges to keep the MMPro from tripping the over-current on the BEC.

We are bench testing a hardware change that will add a very slight delay to the over-current shutdown on the MMPro to compensate for the JR servos.

Note that we have only seen this behavior on two specific JR servos, and adding some capacitance to the BEC line seems to be a good fix for the issue.

Patrick

[J57ltr]

No such thing as a long boring technical explanation. Thanks for the info.

So could the same thing be happening on the hitec servo as well? What is the minimum amount of capacitance you would recommend?

Thanks

Jeff