Canvassing for a Digital Piano Keyboard

My piano digital keyboard is already with me for years and I am trying to canvass for a replacement. Hopefully I could buy soon if I will be able to find a good one which fits to my requirement. I am looking for a 76-key keyboard but weight should be manageable. A weighted keyboard is really good but this is quite heavy so I am trashing out that idea. For keyboard instruments, mobility is important. The sound of the grand piano voice also means a lot since this is mostly used among the sounds available in digital keyboards. There are digital keyboards which sounds too electronic when it comes to the grand piano sound. 

I hope to have a Korg or Yamaha, but as of now I am not definite which brand or model will I get. It will also depend on the price if its within the budget. I hope to have a new one by next year, that would be an exciting moment for me.