I have run into issues with my Microspirit I do not understand and so I hope that experts are able to help me:

I was using the System in an Oxy 2 without issues for hundreds of flights. Recently I decided to change to 4S. Since I had batteries first I tried higher headspeed during preparation without problems. But when I changed the whole setup by installing the new pinion a weird problem emerged.
After 2 or 3 flights with high headspeed (by calculation it should be around 5000-6000) a wobble on the main rotorhead appeared in some flight situations and got worse. I tried to change the head gain which made things slightly better for a short period but it got worse despite the fact that I lowered the gain to the 20% minimum which I now have running.

The only thing I have discovered this far that is helping is lowering the headspeed. Which I did to about 4500 rpm. But now this problem (that was not observeable before at all) also exists when I use 3S Batteries with low headspeed (But mainly during Funnels). Does anyone have an Idea what could be the cause of this problem (The wobble gets pretty strong at times and i fear for the heli which is why I need to resolve this problem fast)? Since it is getting worse I guess a mechanical problem would be possible but I did not change the system and everything should be set up properly (I did however have some issues with rotor-Blade tracking but I think changing the DFC arms resolved this problem).

Could it be that the Microspirit system is somehow faulty? How can this whobble, without strong correlation to the head gain, appear because of "high" rpm whilst becoming worse so it now appears even on lower headspeeds. Would it be an option to send the Microspirit to the producer for a checkup or should I try making a new setup or changing specs first?

I would be thankful for any help. What would you suggest in such a situation?

Greetings

From description it is almost clear that the issue developed during high head speed and is mechanical problem.
Electronics will not damage from high RPM, but mechanics almost always.
For example ball bearings, head dampeners are first that will worn faster. Bent main shaft or any assymetry in the rotor head will cause oscillations of the model in aileron/elevator axis. So it can look like tail boom is moving up and down usually.
I recommend to change any settings in the FBL unit as the last thing you will try. If something will change on its own then it is basically always mechanical issue.
Changing FBL settings to make it less apparent will only hide the problem for some time, but it will get worse over time.

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Spirit System developer

Thanks for the fast reply.

Today I flew lower headspeed again and the problem got better over time. I think it is a combination of mechanical problems due to wear issues. For example I discovered that the microspirit case is loose on one side. It can be moved up and down 1 mm on one side (the whole upper plate with the cable connections and the cables moves). Maybe this happened because of a crash in the past. Can I repair this?

I am thinking about disassambling the unit to look if I can stabilise it somehow. What I will do for now is use some Velcro to stabilise the unit. Come to think of it I have been using that up until recently anyway but I removed it because I thought its no use, this really could be it. I will see tomorrow.

Normally there is no way how electronics could move inside the enclosure.
Only possibility is that two screws are loose or there is severe damage to the electronics or something is badly bent.

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Spirit System developer

Since a tight velcro seems to nearly solve the Problem, i think the microspirit case is the main cause (also the whobble is definitely mainly on the aileron axis).

Here a picture of the situation: https://ibb.co/PZb477L (The case can only be opened on the right side on the picture)

Should I pry the whole case open and see if I can fix it?

Unfortunately enclosure is damaged very likely. It is possibly bent and/or screws are very loose.
Certainly this will cause a problems in flight.

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Spirit System developer

Should I try to repair it myself or send it in?

If it is under warranty than please send the unit to us.

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Spirit System developer

I guess it is not. I got it from a colleague who bought it approximately around 2017. I could maybe ask him.

I guess there is not much to be done, because even only with a tight velcro it works reasonably for a 250.

Just for completion: The Problem was actually a damaged Servo not the microspirit