I have an error message: E-940. Can anyone

E940 - Main Switch Error

The detection mechanism is as follows:
· The machine reaches the auto-off time.
· The solenoid mounted inside the main switch turns on for 3 seconds.
· If the main switch does not turn off, the solenoid is turned off for 1
seconds.
· The solenoid is once again turned on for 3 seconds.
· If the main switch does not turn off at this point, the solenoid turns off
and E940 lights.
Possible Causes -
The main switch is defective.
The main control board is defective.
1. Turn on the main switch.
2. Enter SP5-810 (SC code reset) and press the Enter key.
3. Exit SP mode and turn the main switch off and on.

You might try rebooting it by pushing * and # together, at the same time for about 10 seconds. You'll see the display go dark for a second then come back up again.