Sanyo DC TS760 Can't get bass speaker / remote to... Bought this Home Theater system (2nd hand)

Question

Bought this Home Theater system (2nd hand) and dont have any instructions. the remote seems to work but wont turn up the volume so I assume there could be a problem with it, the ''audio'' button doesnt seem to work neither, I'm presuming you need this function to work in order to turn on the bass as there is none working??

The small speakers work fine but I just cant get the bass to work!!!

Any help would be appreciated as the person i bought it off wont answer e-mails now!!!!!

Thanks