I purchase a an STR-DN1080 amp a few days ago and started to set up using the amp menu displayed on the TV. 

After making some adjustment, the menu disappeared from screen all I could see were multicolour vertical lines  and hissing or crackling sound . The AV amp remote also seized and wouldn't respond to any buttons. I had to switch the amp off and take the electric plug out. After waiting for some time, I switched it back on and it worked, then the next day it happened again. 

It seems to happen at any time into the setting menu or on any type adjustment being made. Sometimes it doesn’t happen at all.