I have a new comparator modle HI-08CS. Also have a radio shack 12v 500ma ac adapter.I hooked up the black and red wires .The adapater has a black wire and a black with a white strip on it wire. The direction in step 2 said "to adjust the right insert size for use from the front panel in the back side"(what does that mean?) I put a wheat penny in the front where it said to replace the plastic coin. Any help would be great.