M8S+ Problem with a/v output

[romo]

Hi I recently purchased a M8S+ android box & have been very pleased with it. I initially purchased it with the hopes of using it in a room that has an older tv with no HDMI hook up. I did not think that this would be an issue since the box had a a/v port. The unit came with an HDMI cable but no a/v cable. Not a big problem since i had one from another device. I hooked up the device where i wanted to use it but could not get it to work when hooked up with a/v cable but worked when i moved it to another tv & hooked it up with HDMI cable. Any help as to why the unit will not work with a/v cable will be greatly appreciated.
Thanks.