E-03 is always an indication that the cassette take up spindle is not turning properly, and this is in most of the cases caused by a faulty cassette, so even although a new one has been installed you have to try another. Another point is that when any tape has been installed give it a rewind or a fast forward as the case may be "before" trying to play it, as this helps to free up both the cassette and the spindle drive system. If however nothing helps then the case will have to be removed for a proper inspection to be made of the mechanism. PS: if you can see the "take up" spindle top with the loading door opened try turning it slightly with a suitable object to make sure its not jammed.