The dryer runs and after awhile the illuminated digital board goes out..like it has shutoff, but the dryer continues to run. I have to unplug it to get it to stop. But when I plug it back in it is still running..have to leave it unplugged for hours before it returns to normal.. but after it gets turned back on it does it all over again. Any ideas as to what is wrong??

sounds like your thermostat is not working. first check the sensing bulb to be sure it is not ice encrusted, that will insulate it from feeling the actual freezer temperature. if that is clear, your thermostat need to be replaced.

Could be the thermostat has gone bad,or timer or heat control board

The element is probably shorted to the housing I have seen this many times be sure to unplug be for checking

I have an educated guess for you. A part of each control of a washer and a dryer is a little electric "clock". Those things can fail. I sounds like you may have a timer clock that is sticking and not advancing.
These " clocks" are a part of the times, and are not sold separately.
One way to possible tell would be to put your ear to the area of the control panel where the timer is and listen. Most of those "clocks" tick, and you can often hear them, or you can watch the dial, and it should advance with a click every so often.
Be blessed.

There are more parts to check and figure out this issue. Check door switch, then temp thermostat.

if it has continuity it's good and isn't the problem,if the dryer starts and stops running after a minute you could have a bad computer board,when it stalls try tapping on the board and see if it starts,also unplug it and look at the board you might see something cooked on it or a soldier joint melted.

This has to do with the control board failure. The control board runs every aspect of the dryer and will need to be replaced. Here is the new control board.

Your belt has broken, Should be able to hear motor running and should sound smoother than usual.

Have you tried unplugging the machine for awhile to let the board reset?

The control board regulates the timer functions, yours may have failed