Roland CR78

Roland CompuRhythm CR-78 ...Help Needed please.... This drum machine has a fault issue and is powering up...But not working... All 5 small front Led lights are staying on and not pulsating of flashing when any preset Rhythm patterns and drum beats are selected... No audio sounds are coming out... But the unit powers up ...Can anybody help at all or advise on what things to try, check, test etc to see if we can get this drum machine working again...please ?
Write me at: Sploj3@yahoo.co.uk

Google https://www.manualslib.com/manual/999992/Roland-Cr-78.html for service notes,,they may help.