Hello .
I just got my hands on an type1 from 1965 in bad shape.
Found a funny type of adapter mounted between the speedometer drive cable and the speedometer itself. The "thing" is marked with number
271941521A and Tachowellenschalter. Two cabels on it, one to the fuse box and the other one disapeares in to car. Have not been able to track were it goes.
BR
Lars