Checkline DT-311J - Manual (Page 9)

MODE 2/4 1 2 5 6 9 10
ON 2 3 6 7 10
ON 3 4 7 8
ON 1 4 5 8 9
ON 1 2 5 6 9 10
9. LAMP ON/OFF SWITCH
LAMP ON/OFF switch provides power to the lamp. To save the flash tube
and general
lamp life, turn the lamp off when not in operation.
Once power is applied and no adjustments are made during the next 30
minutes, the flashing will automatically turn off the lamp causing the
display to flash rapidly. To continue operation, press the LAMP ON/OFF
switch and the flashing will continue. for another 30 minutes.