recurring blank screen on A64+ with ubuntu image & any desktop gui

[faddah]

hi all,

i'm writing about a recurring, annoying issue. here's my set-up —

• Pine64 A64+ board with 2 GB RAM
  
• ubuntu image running from @longsleep's ubuntu image 20160403-1, on a class-10, uhs-3 MicrosSD (thank you, @longsleep!)
  
• also, after running the script to expand the partition to use the whole MicroSD, i installed the xdesktop-ubuntu for a window manager/gui (but i have also seen this happen on Mate or XFCE4).
  

when using the xdesktop-ubuntu window manager/gui (or Mate)(or XFCE), the desktop works fine for a while, but then randomly (and i haven't any one thing that causes it — could happen while dragging a window somewhere else on the screen, could be when i open a second or third window or app, could be during a long apt-get install, often, after a while, after log-in, it goes straight into the blank screen every time) it goes to a blank screen that i can't get any response from the keyboard or the mouse. i end up having to cycle the power on the board and restart to get out of it, every time. after a while, as i stated above, it tends, after gui log-in, to go straight to the blank screen, every time. i then have to unplug the board and let rest/sit for about a half an hour or more before trying again.

the blank screen can be a variety of colors — all light green (like the Mate desktop color scheme or the background pic i chose for xdesktop/ubuntu; could be flat slate grey; could be all light grey/white. it depends on what was last on the screen before the blank screen freezes everything.

• any ideas on how to solve this or get out of it without a restart when the blank screen problem hits?
  
• has anyone else seen this?
  
• anyone have any solutions to this?
  
• is it a heat/heat sync issue? do i need a fan on the board?
  
• is it going to be an upcoming firmware fix to the board? a fix to the ubuntu image? both?
  
• is this similar to the DMA problem i read about on with the a64+ 2 GB board with the Arch Linux image issue?
  

any help in getting this resolved, please, so i don't have to restart the board a couple dozen times a day to get things installed or done would be most appreciated. thanx in advance.

best,

—  faddah
     portland, oregon, u.s.a.