Does anyone have any info or experience with this mixer? I believe it is a Romix I have acquired one that seems in decent order but have a couple of questions: Should the drum have teeth all the way around or 'sets' of teeth evenly spaced around the drum? What chain should this model have on? Having cleaned it up it seems to work 'okay but does have some chain slap or slip? Just wondering if the chain is stretched? Any help/info much appreciated!