mini dv recorded noise

can anyone help with this problem
have a sony dcr pc110e aprrox 6yrs old and 30hrs use (no of tapes used).on my last 2 jvc tapes i get intermittent sound drop out to be replaced with what sounds like somebody squashing a bag of crisps/ white noise.it occurs randomly and on 2 diff tapes.tapes are new and aprrox 2 yrs old but never unwrapped until now.it happens when filming inside (so not wind noise) and outside.have cleaned heads and replayed and still same.any help or ideas much aprreciated thanks to anyone who posts reply