[mickash]

It's also worth checking whether the black grease on the worm gear still is grease-like. The grease in some VCRs deteriorated into an almost rubber-like substance causing the gears to stick and putting strain on the motors and belts.

If the grease has gone like this it should be cleaned off with a solvent like IPA or meths using cottons buds or an old toothbrush. The gears should then be re-greased using Molycote or similar.