i have a sanyo music system but no remote, everytime i press a button it goes into sleep mode, how can i fix?

[j.j]

it is a sanyo DC-F410U, fairly old but in good nick. when i plug it in the display screen lights up and flashes, but once i press any button i;s like it goes into hibernate, where the display screen goes dark except for the digital clock that is the only thing that is lit. tried the reset button at the back, while it was on and when it was off, and trying holding it for a minute to no avail. any help would be great