Swash plate wrong compesate action on alt hold/loiter mode

Cheap APM 2.8 from ebay. Heli class 500 flybarred. Traditional helicopter firmware 3.2.1

My APM 2.8 installed for traditional helicopter, the swash plate servo has reverse action when i changed the mode from stabilize to alt hold or loiter mode.
When on bench. When the heli tilted to the left, the swash plate automatically move to the right.
But when i changed to alt hold or loiter mode. Swash plate action was reverse, when i tilted the heli to the left, swash plate also move to left (the correct action should move to the right)
I also could not operate the swash plate servo from TX during alt hold and loiter mode.
This problem caused my Heli fly away during this mode (alt hold/loiter).
I already reset to default and upgade the firmware to beta firmware but the problem still exist.
I also already buy new APM board but the problem not solved yet

Did you ever get this issue resolved?

I haven’t purchased a unit but trying to gain some knowledge of issues prior to installation.

My first thought is that that there is a +/- issue at hand…kind of like changing parameters in the radio–when pitch/roll etc is going the wrong direction-- just change to the other side of zero.

is it mounted upside down?

Hi There ,

I am flying an apm 2.8 on my 550 heli too and it works fine .
Does you Heli fly correct in the Stabilize mode ?
In stabilize mode it should drift the the left - cause you backrotor will push it in this direction to handle the momentum of the main rotor .
Where is your APM/PIX mounted and how are the vibration levels (get them from logfile).
greez ,