One of the most common failure modes of the Dual 1219, 1229, 1229Q and 1249 turntables is a frozen single/multi selector lever.  If your lever seems stuck, do not force it, as it will break a very difficult to find component.  The problem is a hardened rubber retainer which grips the two steel balls on the selector shaft (see pictures). The rubber retainer will eventually become brittle and crack. This auction contains a new rubber retainer to replace the Dual part number below:

(Qty 5) Dual P/N 216 845 - Rubber washer