what do the numbers 33 mean when they are displayed on the display window?

i have a panasonic dvd recorder number dmr-ez45vebs , everything appears to be ok, but when in standby mode, the numbers 33 are constantly on display, when the unit is switched on three zero's are displayed , this is because the clock/timer has never been set, when discs or vhs tapes have been played and finished, the numbers 33 appear and stay on until the machine is started again, can you help/