Controller locks up and is unresponsive

[drew7977]

Newly repaired controller locks up after a few minutes of use.  The unit display is lite saying unit id but when you hit select nothing happens.  If you turn off wait 30 seconds and turn back on it comes back for a few minutes then stops again.  Whatever lights are on at the time of lock up stay on until power is cycled.  If you unplug the network cable and turn on it displays no connection then that to locks up and won't scroll.  HELP!