I went to Panasonic's as I was getting dropouts with Sony tapes back in 2000.
I once put in a tape from a relative's old mini dv camera and it completely stoped my 3CCD camera from viewing and recording tapes. It instantly gummed the drum so much it just would not play any tape after that.
I then put the tape in another camera and it did the exact same thing. No head cleaner would then fix it, thinking I will now have a very $$ head repair.
So I got myself a tin of $8 Xylene and carfully cleaned the head drum with a cotton bud making sure the zylene did not touch any plastic as it would of melted it.
A few minutes later and a test clean with a normal head cleaning tape the cameras came back to life.
If you do this be very carefull with using Xylene, it's very strong but it cleaned the head up perfect.