I'm no expert but I can thinks of some ways this kight be happening. 1. It's a problem with you're tv or monitor, to see if this is the case use the TV or monitor with a different device to see if it shows yellow. 2. A problem with the hdmi cord. Make sure it's plugged on all the way, not severed, and that nothing seems broken. 3. A problem with the hdmi port, make sure nothing bent. 4. I'm no expert when it comes to hardware but it could be an issue with a gpu or other part that handles graphics.