Doorbell AC DC Wires

I am trying to set up a door bell which requires ac/dc.

There was a door bell there but it did not work,.. however the buzzer that buzzes the door open which is connected to the same system does work. According to previous owner, the bell just stopped working at one point.
The old bell was connected with 2 wires.. Green and White.
Blue and Red were wrapped in a plastic like cover,.. Yellow was trimmed off and wrapped around.

How can i tell which one is DC and AC? I tried using the same wires as were connected before and it didnt work,.. tried other combinations,. blue and red, etc...

Please help.

Thanks

 

Welcome to the forums.

If you mean the button was connected to green and white then those are the two wires that control the doorbell.

If you have a doorbell system then the problem may be there.

 

I've never heard of a split AC/DC doorbell system. Maybe it's because it controls the door strike too?

Can you see these same wires on the other end? As far as I know, there's no standard color coding to doorbell wiring.

 

The green and/or white wires could have been broken inside the wall perhaps because a squirrel got inside and chewed them.

The button upstairs that controls the door strike buzzer might be part of a panel with wiring behind that includes the green, white, red, and blue wires. If the red and blue are not being used for anything else you might substitute them for the green and white at both ends and see if the doorbell works.

Or maybe the green and/or white and/or red and/or blue wires go down to the button outside the front door and you can substitute wires from that location up to the bell unit.