GY520 Wiring

[fedex]

Here's my issue. I'm replacing the gp790 for this GY520.
Looks as if the 4th wire (yellow) on GP790 was tied into the red plug(bec), and I'm not sure why. With the GY520 there is only 3 wires on each of the plugs.I'm not really sure how to make the change in wiring here.

[Gladius]

I've never used that gyro, so take what I say with a grain of salt...

Most gyros have the normal 3-wire servo plug that connects to your receiver's rudder channel, a 3-wire plug that connects to your rudder servo, and a 1-wire plug that connects to your receiver's gyro channel.

It looks like someone decided to combine your single wire plug with your BEC power lead. That works just fine, since the gyro lead plugs into the signal slot of your gyro channel, and the BEC leads plug into the positive and negative(ground) bus. It's a space saving measure for use in a receiver that doesn't have extra channels to plug the BEC lead into.

You can pull the yellow wire out of the BEC plug, and continue to use BEC plug like normal, or you can add the gyro channel from your new gyro to the same plug.

[fedex]

Ok, so I reversed the wiring back to "normal". Just trying to simplify things. two plugs on the gy520 dongle. "black" Tail rotor channel, and "red" Gain channel. Does this wiring look correct? does anything need to be plugged into the gear channel on the rx? I'm thinking the BEC connects to the Gear channel instead of the gy520 dongle? But that leaves me with no place to connect the Gain channel on the Gyro. Only see two ways to wire this. First pic or the Second pic with the gain channel on the dongle not being used.

[Gladius]

You need to have the gain channel connected to your receiver. You can only run the BEC thru the dongle if it has a common positive and negative bus. And that also runs ALL of the power for your electronics thru that dongle. I wouldn't do that.

You should be able to plug the BEC into the bind port on your receiver, and connect the gyro wire between your dongle and the gear channel on the receiver.

Also, in the second picture, it looks like you have the BEC plugged in backwards. Brown and black wires are usually ground wires, while white and yellow wires are the signal wires.

[fedex]

I'm confused now... Use the gain channel (red Jumper) on the dongle to connect where currently the rotor channel (black jumper) connects to the rx? Just remove the black rotor channel jumper? The Gy520's manual isn't exactly that friendly. Thanks for all the help in advance.

[Gladius]

The Rudder lead (I believe that is your black jumper) should connect to the rudder channel. The Gain lead (red jumper) should connect to the gear channel. The BEC lead should connect to BIND... but it should only have 2 leads (red and brown). Why does yours also have a yellow lead?

[fedex]

Just the way it was designed I guess "10 amp castle bec." If I use both gain and rudder channels on the dongle, that leaves no room to plug anything else into the receiver. 3 connections, 2 channels available accept the binding port.

Rudder and Gear ports are the only two the other gyro and BEC accommodated on the previous setup. So I changed one thing and plugged the BEC into the binding channel and left the 3rd yellow wire in the plug. So now all channels on this receiver are accommodated.
Does this look right?

I disconnected the motor and powered it up... Everything seems to be working minus calibrating the gyro! If you see anything else wrong just let me know.. Thanks so much for your help!

[Gladius]

Yep, that looks right to me!

Also, I pulled out a Castle BEC that I have, and it has the yellow wire too. Then I remembered that the yellow wire is used when programming the BEC with the CastleLink software. When plugged into your receiver, it doesn't do anything (I believe). So you should be good to go!