Vince,
I did some research and I believe you are correct. I would have never imagined a cable driven hour meter. I could not find any reference for the DK35 and saw in the Dealer brochure on the DK35se that the hour meter was electric.
So I performed an internet search on mechanical hour meters in tractors. I was actually amazed how they work. They are set-up as a counting mechanism. Over a certain RPM, like 1600, it basically counts gear teeth and converts them to an hour. However, below the set RPM, it assumes a partial hour. So these were referred to as RPM hours. The justification for this is that most tractors were run at an RPM for the PTO. As more tractors were used for other purposes, lower RPMs were common and the electric hour meter was necessary. So, if you have two tractor idling next to each other, one with the mechanical hour meter and one with the electric hour meter, the mechanical hour meter will show a lower count by the end of the day.
