600 Dominator

[SteveC1962]

I have bought one of these and built it but when I took it to the club for some assistance with set up everything was going fine until we got to the tail and discovered the tail servo would only work if "assisted". We decided the servo was faulty so I sent it back and in the meantime bought another and installed it.

I took it back to the club today to set it up and initially during set up the tail servo was fine but when we went to check it stopped working properly and it needed "assistance" to move, just like the original!

Its the standard kit and servos, I'm using a receiver battery without any BEC, anyone able to shed on light that may resolve the problem.

Thanks.

[jimmyhorns]

Do you have the tail servo's frequency set up properly in your FBL unit?... i.e. frequency e.t.c.

Do you have your tail servo end points set up so that there isnt binding?.. as this can cause a tail servo to burn out....

What voltage battery are you using?... and is the servo rated for it?..

[Grumpy]

What pulse rate did you set in the FBL controller 760us or 1520us?

I understand that the new Align BL855H tail servo is still traditional wide band type (1520us), which is surprising. If set wrong it wont work properly, if at all, and may damage the servo.

[bigbladelittleblade]

It could be your gyro settings in your transmitter, make sure that it's not set to 0%

[ghl001]

Hi Guys,

The servo is a BL855H - High Voltage servo, GPRO FBL controller with an Align 7.4V 2200 Lipo driving it. The Pulse rate is set to 1520 and the gyro does have a value.

The servo worked initially, when setting the end points, then when get to the end of the setup there was no heading hold, we increased the gyro to get heading hold. The servo just seems to stick. When moving the rudder we need to push the servo a little for it to work, when moving the rudder the other way, again we need to encourage the servo to start moving.

When in the neutral position the servo is well locked, it just doesn't move without a little assistance?

We tried the servo on another Gpro and it was still the same and when we connect another servo to the Gpro it works fine. Seems strange that this is the 2nd 855 to have this issue on the same model?

[Grumpy]

Sounds very much like like a burned pot on the servo. I have heard several reports about faults on the new Align HV servos.

[SteveC1962]

Thanks to ghl001 for filling in the blanks, was out and about.

Hi Grumpy, this is the second BL855 with the same issue, we thought the original had a problem straight away but it had the same problem as the new one now. Bearing in mind the current one was okay until we checked the heading hold, why would it burn something in it at that point?

[Grumpy]

why would it burn something in it at that point?

The simple answer is of course 'it shouldn't'... But if these servos all came from a faulty batch?

If the servo is sticking around centre then that point to a burned pot near the centre position. That would usually make any binding issue unlikely to be the cause because you would expect to see binding well away from centre, so the pot would burn away from the centre position.

The fact that it works fine when you connect a different servo to your FBL controller, and this servo fails to work when connected to a different FBL controller pretty much proves beyond doubt that it's a servo fault.

[p4ddy]

My servo was doing this on my logo when I set it back up because I kept forgetting to click the correct servo type

[SteveC1962]

After checking out youtube by the looks of it I should be replacing the Align servos or leaving the Heli on a shelf!