T-Rex 250 Gyro setup

[Milamber]

Hope someone can offer an insight into this. Just completed a 250 SE all stock, so 780 gyro and 420 Tail servo. I have completed the setup, but, the servo drives hard to one end at power up and will not move in response to the Tx stick. This happens either HH or rate mode. If I unplug the ESC and plug back in again, without switching the Tx off, the Rx "blinks" - normal, but the gyro initialises and the tail servo sets up and responds correctly. Wierd or what. Hope someone can help, I'm stumped.

Maurice.

[msssltd]

Check the servo timing setting on the gyro. It should be set to slow for the D420.

[Milamber]

Thank you for your response Matt. The default settings call for 1520 and then digital servo - items 1 & 2 on the setup list to show green and green on the LED and this checks out. I have also noticed a ***very*** soft "softstart" so think I need to replace the ESC. A pain in the rear end, but fortunately I have an older one which may suffice. Thanks again, regards.

Maurice.

[msssltd]

Thank you for your response Matt. The default settings call for 1520 and then digital servo - items 1 & 2 on the setup list to show green and green on the LED and this checks out.

I am far from an expert with these things but the only time I can recall seeing the behaviour you described, I had inadvertently set the gyro for a narrow band servo.

I may have seen something similar during an attempt to set the tail slider limits, so it might be worth resetting those too. I can't remember whether it's the 750 or 780 that is a little awkward, in so far as it does not behave quite the way I expect from the description in the manual.

The soft start on the ESC is a lot softer than other soft starts I have experience with (E-Flight and Pentium). I guess it takes somewhere between 5 and 10 seconds for my 250 to spin up. I just know I have to keep reminding myself to be patient and not take off while the rotor is still coming up to full speed.

Best of luck sorting it out.

[CookieMan]

Hey Maurice,

Double check this setting: HELICOPTER MODE AND DELAY SETTINGS (Function 8, on the Manual).





The LED must be set to RED and NOT green, for smaller helicopters. Does this setting get on when you unplug the ESC and reconnect it, the second time around?





Cheers,

[Milamber]

Thanks for the input. Unfortunately that setting is "Red LED" at all times I have decided on a different ESC to see what that will do both the other 250's behave correctly.

Maurice.

[cupracing]

This seems like regular behaviour for the gp780 and is also found on the gp750, I believe it a quirk and nothing to worry about. I have owned a few of both variations and every time I have plugged it in ,the servo moves and doesn't centre. I have to cycle the power a few times in order for it to centre. If I don't turn the tx off between each cycle the rx will blink. The blinking doesn't result in the rx not working properly and I have flown many times with it doing so. I do prefer the static light though so cycle the tx power also to get this. Hope that helps

[Milamber]

Thanks for your thoughts Andy. I replaced the ESC this morning and all's well with the second one . Got the trim sorted and spent 3 or 4 frustrating hours trying to fit the F3C fuz to it. Absolutely nothing worked for me on this. Must dig out the mag where it was reviewed and see what in tarnation the reviewer did to shoehorn it into the fuz. Thanks to each of you for your advice, it was very welcome. Regards.

Maurice.