Lost connections display while operating Mac Mini

Hi,

When i got my Mac Mini and attached to via HDMI port to Sony Bravia KDL35, it seem okay but i'm struggling with the resolution.
Later on, my Mac Mini work with dual monitor setup. How ever from the early beginning the problem start to rising up. Begin with wake up problem (solved) and lost connection (unresolved). I believe the Lost connection not only affecting the monitors but with all other external peripherals (wireless logitech keyboard/mouse, USB external HDD, USB printers). From all of these, annoying flickering on and off screen display are seem to be the big problem and can be watch and observe as a failure of the connection.

Updating OS X Yosemith from factory default along the way, fixing the Monitor wake up problem.

Up until El Capitan the lost connection in the middle of operating Mac Mini seem to be no working solutions yet. Please help. Thank you.