E-03 is a warning that the cassette take up drive spindle is not turning properly, and this can in many cases be caused simply by the actual tape used being faulty (internally sticking) so another tape must always be tried. Continual use of non JVC can cause problems with JVC devices, and TDK or Maxell tapes should never be used, as its known in service circles that there is a high incidence of drive problems where these brands have been used, always stick to JVC - Panasonic or Fuji tapes. However if another tape doesn't cure the problem then it indicates that the take up mechanism will have to be inspected, which obviously requires an element of dismantling to be carried out. A long shot measure which sometimes helps is, with the cassette holder open blow air into, and onto, the spindle area, a hairdryer on its cool setting is ideal for this, as if tape dust contamination is the cause of the problem then this might clear it.