AltHold, Loiter - altitude is not holding

I build my first quad and i got this problem:

Stabilize, auto and brake modes are working perfectly. But AltHold, Loiter and PosHold have same problem. Copter did not stay at set altitude.
In althold mode - i increase throttle and copter is going up, then i move throttle in the middle and copter is still going up, then i switch to brake mode a copter immediately stops moving.

What i try:

  1. Check Throttle hover
  2. Check throttle deadzone
  3. Try it with and without sonar
  4. Vibrations - in Towel vibrations is green and brake mode is working
  5. If there is enought thrust

PX 2.4.8
Taranis x7
noname ESC
4x DJi 2212 motors 920kv + 10x4,7 prop + 3s li-po
total weight 1.2kg
fw 3.4 stable

Thanks for any ideas…

Is your copter maintaining its altitude in Stablize mode with a 50 % throttle?
Otherwise, a copter in Alt Hold Mode could climb or descend

Have you tried to modifiy the deadband with the THR_DZ parameter?
Or better


yes, in stabilize copter hover in 50% throttle, average motor output in hover is about 40%
THR_DZ parameter have default value - 100
Automatic learning of hover throttle is on and it is working…


A copy of your flight log would help anyone looking to see what might be going on.

Please help me with a similar problem. My log

I removed buzzer from pixhawk and everything became normal. Thanks to all