If you have "liquid" cleaned the video head and it didn't make any difference, then there is basically nothing further of an external nature that you can do, as the e-04 code is associated with problems concerned with the video drum or the ribbon cable connections to / from it, needless to say dismantling is necessary to enable a proper investigation to be carried out. Note! When you referred to the video head having being cleaned, if this was done with a "cassette type" cleaner then it may still not be properly cleaned, especially if there are any hardened-on tape dust deposits on the heads, however I cannot send the "wet clean" instructions as it has to go direct to an e-mail address as it contains a JPEG for illustration purposes. Problems can be expected in JVC machines if tapes other than JVC - Panasonic or Fuji has been used, TDK or Maxell being brands that should not really be used, as its known in service circles that these brands can be the source of problems. (only in JVC machines!)