The part before the solo has for the most part have had a backing track; for 1987-2012 it was the one downtuned from the original song itself. For the SWW tour Jon screamed on top of it, then on the two succeeding tours he's wildly inconsistent (sometimes he'd sing, sometimes he'd just lip-sync the way out of it, hence the stink eye in Chile 1990 when the track failed to play).

TD onwards he'd sing the part, then the track was dropped from LH (when he changed the way that part is sung) until BWC. Then during the first night at Macau in 2015 they used a new track to lipsync to (after all, given the state of his voice, it's more believable to listen to a nasal backing track than, say, the original recording. Not to mention the latter is inconsistent with the way he's been singing it for the past 10 years). The Greenville soundboard shows the he still sings on top of it, which is why I'm puzzled at why he still continues to use it.