You can lock the control panel by holding the up and down arrows at the same time for a couple seconds.
Steps to unlock the control panel:
- Press and hold the set button until it enters the setting mode.
- Click the set button several times to get to the LCK setting.
- Press the up or down button to set the LCK to zero
- Click the set button again (this is to save the setting)
- Press and hold the set button to exit the setting mode.
Is the LCK parameter to zero as shown in the picture below?
If the LCK is not set to zero, then the up and down buttons will be locked.
