Roberts Radio R972 - Manual (Page 26)

Auto power off
In order to save battery power the R972 is designed to automatically
switch off after 90 minutes of use, the symbol
will appear in the
display when the radio is switched on.
To disable the auto power off function, press and hold down the power
button for more than 2 seconds when turning on the radio. The symbol
will be removed from the display.
Deep Bass Boost switch
Setting the DBB switch (12) to the up (On) position will enhance bass
sounds. Return the switch to the down (Off) position to restore normal
operation.