View Full Version : 401 and T-Rex 450 problem???

05-23-2008, 05:41 PM
I've got it installed and everything is going in the right direction. Everything is lined up straight but here is the problem. I am using a 9650 servo. The DS switch is on on the 401. Everything is correct in the radio as per videos on the web. When I tested the servo without it being plugged into the gyro it worked fine. When I plugged it in it is very very, doesn't really center properly and makes a little intermittent sound, kind of like Morse code. Nothing is binding. Delay is set to 0. Any help would be greatly appreciated from this newbie. Thanks.

"No honey, you wait in the car, I'll only be in the hobby shop for five minutes."

05-23-2008, 08:52 PM
Knowing your transmitter would help. HH gyros need Revo disabled. DS mode is correct. Initially I would say your gain is too high .... should start around 66% and work up until it starts to twitch then back it down. You should be turning the heli on in HH mode and not moving it when turning it on. Any movement will start the gyro working and it will not be able to reposition if not running.

05-24-2008, 01:47 AM
I'm using a DX7 and no Revo. I'll try setting the gain to 65 and see what happens. Finless Bob has a great video on 401 setup on a T-Rex 450 -- unfortunately it's done on a Futaba radio. What bothered me was the big difference in servo action when plugged into the gyro. Is that normal -- to see a change in movement like I'm getting???

05-24-2008, 01:50 AM
On one of the videos (kinda hidden), the DX7 is set at 75 for the gain on the gyro. Works great on mine.

05-24-2008, 01:54 AM
Thanks. I could not have built this helicopter without the Finless videos. Full stop.
I also used the Jermo one to set up the DX7. ;) Speaking as a heli newbie I don't know how guys do it without that kind of help (unless they have a friend who flies and has experience building).

05-24-2008, 02:50 AM
Those still aren't the vids that I'm thinking about. After 10 minute of searching, I finally found it. You can get it here...
Download video "Tail Servo and Gyro 401 Setup". It deals with the DX7 and GY401.