Can someone please help solve two Dynon problems? I have an RV8 with a Dynon FD180, HS34, pitch servo and roll servo.
The FD180 worked fine until the HS34 and servos were installed, along with the 5.1 version of software.
The first problem's symptoms are:
1. Just as power is increased for takeoff, the DSAB fail warning comes on, typically followed by the "Lost HS34" warning after takeoff. Both warnings can be acknowledged, and the FD180 continues to function. Usually before departing the pattern the "Lost Roll Servo" then "Lost Pitch Servo" warnings come on, and can be acknowledged.
2. Shortly after takeoff, everything operates normally: The HS34 functions properly; the autopilot can be engaged in both axes.
3. Everything seems fine until arrival at the next airport, with all of the symptoms in #1 returning. The data displayed on the FD 180 is still correct, but sometimes no other display can be selected (as in shifting from EMI to HSI 1/3 page). On one occasion, no warnings could be acknowledged, and the FD180 unit refused to turn off on landing. On the next leg the FD180 recovered, functioning normally, even after the DSAB and HS34 warnings reappeared!
What we have done so far to try to solve the problem:
1. For trouble shooting, the DSAB and power wires to the servos were disconnected. The HS34 functioned normally, and no DASB or Servo warnings were present.
2. Then the DSAB wires were reconnected, but not the power wire to the servo. All of the problems in #1 reappeared.
3. The HS34 DSAB connection to the FD180 was changed to a twisted pair. All of the problems remained.
4. The wiring to the servos is by multi-strand, shielded wires. The third thing tried was to ground the shield at the servo end only. All of the problems in #1 remained.
Therefore, it appears that the problem lies in the DSAB wiring going to the servos. But what is the problem?
The second problem is instability in the autopilot. The sensitivity has been adjusted to a level that seems to minimize the pitch and roll excursions, but the heading continues to wander +/_ 10 degrees from the assigned heading. Flying in "Course" helps a bit, but the heading never settles out. With only one person aboard, the pitch control is reasonable but not perfect. However, the addition of a rear seat passenger results in a diverging pitch oscillation which becomes more violent and with greater pitch oscillation with time. In other words it appears to be negatively damped. Roll oscillations are also worse than with only the pilot aboard. Can anyone help with this?
The FD180 worked fine until the HS34 and servos were installed, along with the 5.1 version of software.
The first problem's symptoms are:
1. Just as power is increased for takeoff, the DSAB fail warning comes on, typically followed by the "Lost HS34" warning after takeoff. Both warnings can be acknowledged, and the FD180 continues to function. Usually before departing the pattern the "Lost Roll Servo" then "Lost Pitch Servo" warnings come on, and can be acknowledged.
2. Shortly after takeoff, everything operates normally: The HS34 functions properly; the autopilot can be engaged in both axes.
3. Everything seems fine until arrival at the next airport, with all of the symptoms in #1 returning. The data displayed on the FD 180 is still correct, but sometimes no other display can be selected (as in shifting from EMI to HSI 1/3 page). On one occasion, no warnings could be acknowledged, and the FD180 unit refused to turn off on landing. On the next leg the FD180 recovered, functioning normally, even after the DSAB and HS34 warnings reappeared!
What we have done so far to try to solve the problem:
1. For trouble shooting, the DSAB and power wires to the servos were disconnected. The HS34 functioned normally, and no DASB or Servo warnings were present.
2. Then the DSAB wires were reconnected, but not the power wire to the servo. All of the problems in #1 reappeared.
3. The HS34 DSAB connection to the FD180 was changed to a twisted pair. All of the problems remained.
4. The wiring to the servos is by multi-strand, shielded wires. The third thing tried was to ground the shield at the servo end only. All of the problems in #1 remained.
Therefore, it appears that the problem lies in the DSAB wiring going to the servos. But what is the problem?
The second problem is instability in the autopilot. The sensitivity has been adjusted to a level that seems to minimize the pitch and roll excursions, but the heading continues to wander +/_ 10 degrees from the assigned heading. Flying in "Course" helps a bit, but the heading never settles out. With only one person aboard, the pitch control is reasonable but not perfect. However, the addition of a rear seat passenger results in a diverging pitch oscillation which becomes more violent and with greater pitch oscillation with time. In other words it appears to be negatively damped. Roll oscillations are also worse than with only the pilot aboard. Can anyone help with this?