Turns completely off after 20 min - Acer Aspire 7720-6155 Notebook

If it is completely dead. Put it on the charger. After 20-30 mins check to see if it is charging.

Sounds like your thermal component needs to be replaced.

When computer starts continuosly press f11 key should take you to repair/recovery options.
Let me know may be a different function key but should display which key on boot up.
Or you can also try a system restore to a date where pc last worked correctly.

unplug it for 15-20 mins to see if it needs to be reset shane

I've got the exact same problem with this unit. Don't have any solutions, however.

Does it shut down completely? If it does, and the timer ceases turning, your problem may be a blocked vent pipe or Lint buildup.Your high limit switch is designed to kill power to your heater coils and sometimes the motor in case of overheat.

if it is doing it automaticly un plug main bais for about 20-30 min

see power settings in control panel.
It must be set on blank screen after 20 mins or something like that.
set it like this
turn off hard disk- never
blanks screen - never

set never with everything


cheers

there is a thermal switch it cuts out the heater element when its at temp. also so has a thermal switch that cut out the unit if it gets to hot. there will be two thermal switches or a combined one. it will have 2 to 3 wire on it and is directly connected to the the drum. one of these is the problem the thermal switch is working as its cutting out the unit. to stop a fire.

timer set in menu options. Mine did the very same thing until I cleared the timer