symphony II 6 cd keeps freezing

Hi all, anyone else had this problem and can advise a fix?

Symphony II 6 CD changer and tape unit

CDs play fine for approx 20 mins and then freezes / shows error

Then cannot eject any discs

Radio works fine and problem is gone by next day, but again, cd playing for 20 odd mins and freezes again

Would like to get it working again ideally until I get my rnse unit

thanks
Dave