EVO: Init Failed, Retrying - With crazy servo jitter

I setup my brand new EVO over the last 24 hours and noticed something very odd.

With no servos/escs/any IO at all plugged in to the EVO i would get a "Init Failed, Retrying...." that would last 30-45 seconds before i would turn it off. I am not touching the EVO at all and it is sitting on a table with a 2s lipo.

This happened maybe 1/5 times i turned it on.


This is where it gets weird... I added servos to the EVO and when this same issue described above occurs, the servos do 1 of 2 things:
1. They go to the stick position and jitter very slowly, almost a slow drift. This continues until i turn it off.
2. The servos make a CRAZY noise with no movement at all, incredibly loud to the point i pulled power as soon as i could.

I'm able to reproduce this by power cycling the EVO, again this happens 1/5x. Usually it'll do it 2-3x in a row on boot up. If it turns on and doesnt immediately start freaking out, the vbar initializes no issue and works as expected.


I am set to 760us/200hz on cyclic and 760uS/500hz on the tail. Worth noting this happened on the bench before i ever set pulse width or frequency...... (init failed, retrying error non stop in the radio) This also happens under BEC power and battery power, and as said above with no IO plugged in i get the init failed log alarms and it never initializes.


Is this a known issue/any ideas?

Hi,

this is not a known issue, with VBar EVO*.

On all VBars, the init should happen within a few seconds, and repeatably.
Reasons for repetition are, either the stick input is not at center, at rest, sticks are moved, or the sensors do not center, do not come to rest, or the VBar or the model are moved (same), and the selftest keeps re-iterating.

What you observe (jitter/slow drift, even noise) somehow supports that, it can be the result of the erratic sensor behavior.

Please return this unit to your dealer, for a replacement.

Kind regards

Eddi

*there was an issue some years ago, where, if you selected 50 Hz servo frequency, for analog tail servos, on certain VBar _NEO_ the init could have behaved this way.
This has been fixed long ago, with a software update..
And it's little-known after all, because hardly anyone uses analog servos any more, swash plate or tail.
I have just tried it anyway now, and the unit initializes just fine.

Born to fly ...
forced to work.

That is disappointing. I will reach out to mikado USA.

Thank you for the response, I’ll try to get a video of this before i send it back.

Is the Evo mounted in the heli with tape or is it sitting loose on the table. If it’s sitting loose and it’s free to move by servo cable tension and servo movement causing the Evo to move etc it will make the servos move crazy fast. That’s what I experienced. My tail servo was moving so fast when I held the Evo in my hand I got scared and power down. It was a blur it was so fast the horn. But when I mount in the heli it was fine.

Yes it’s mounted to the heli. It also does this sitting on the table with just a battery, flat on the table not being touched.

Here are 2 videos:

https://youtu.be/1AXp34wUEHg

https://youtube.com/shorts/tGYR3kz3pZw?feature=share

I’ve reached out to Mikado USA and am replacing under warranty.

Another video to demo what’s happening here, the normal pulse range is 607uS-879uS. Note it goes outside this range and also goes up when the radio sticks are at the top and bottom. It should be linear up/down. Also clearly very twitchy…..

Hopefully this helps fix these EVO bugs.

https://youtube.com/shorts/rHNZmsGX1r4?feature=share



Edited 1 time(s). Last edit at 05/26/2023 01:29AM by tek18x.

Hi again,

hm, this is definitely not normal, but I can't deduce anything from it yet.
If everything's OK, everything should initialize like in the first example 1-2-3-pitch-twitch.

About the pulse range, there's no written standard. Afaik, for 750 (or 760, throw a coin) it's supposed to be +/– 250 w/ or w/o reserve for trims for the narrow pulse, and 1,500 (or 1,520) +/– 500 for the wide pulse.

On the other hand, the VBar doesn't know what's happening outside, servos connected or not, it's concentrating on the stick inputs and on the sensor readings.

Of course, it needs a considerably stable voltage of 4+ V to safely initialize the sensors.
If the voltage would somehow be too low, the sensors would not work properly, and if the voltage was not stable enough, fluctuations could have effect on the centering/settling. Of course it's all buffered somehow, to make it as safe as possible, but e.g. with certain (different) ESC's BECs, we have seen continuous repeated initialization like 8/10 times, while with a buffer battery, all was good 10/10 times.
YGE's supposed to have one of the best BECs these days, though, it's just experiences from the past I'm sharing.
This is why, if in doubt, when troubleshooting, use a battery instead of an electronic power supply, and also try w/o servos or also with different servos, type, brand.

Anyway, I'm curious what we find once this unit reaches our service shop.
And I'm curious what you find, with the new unit.
It's a first after all ...

Thank you for your efforts so far!

—Eddi

Born to fly ...
forced to work.



Edited 1 time(s). Last edit at 05/26/2023 11:07AM by Eddi E. aus G..