Repair tip
I'm starting to do rebuilds on these Klopp coin counters for friends. One thing I've noticed with older ones (20+ years old) is there is a problem with the coin gauge knob slipping out of place and out of adjustment frequently. This is because the setscrew in the Coin Gauge brass worm gear (# 93-53702) has broken off inside the Coin Gauge Shaft (# 3-5210). This prevents tightening of the gear to the shaft so it slips and causes problems. The cure is to buy a replacement 3-5210 shaft (it includes new setscrew and the roll pin for the knob is pre-installed). The shaft has a pre-drilled hole in it that the setscrew will mate into (prevents slipping). That hole correctly lines up the shaft, gear, and knob. When the knob "5" (nickel) position is up, the hole in the shaft should line up with the 5 on the knob. Tip: put oil on the entire length of the shaft. Then put the knob on (a new setscrew for the knob is also included with the new shaft) and this makes it easier to assemble the whole coin gauge unit.
EDIT:
When ordering parts, always give the model AND serial number of the machine. There were some changes made over the years and this will ensure you receive the correct parts or complete modern replacement assemblies.