need assistance with adding camera to existing system

[brian1980 0]

Hello,

I installed my own dvr and cameras several years ago.  I work in IT, but I'm not particularly versed in surveillance systems and could use some assistance.

The DVR I installed is an Everfocus ECOR HD 4F.

 

At the time I only had three cameras connected to it...and everything was working great.

The three cameras are:

2- EX760

1 -ED910

 

I recently needed to add an additional camera.  

So I went with this one.  EZA2580 eX.HD series

 

When I plug the new camera in, it doesn't work.  But if I unplug one of the old cameras, it does work.  I can get 3 cameras going at once...but not all 4.  It doesn't matter which cameras or inputs I use either.  

 

Can someone please help me figure out what is going on here?

If I need a new DVR, can you recommend which one I get for this camera setup?

 

Thanks all!