George, I too have an old Simpson 260. The last time I tried to use it, it wouldn't work. I suppose the switch contacts are corroded from lack of use.
The reason the old analog units had a zero adjustment wasn't so much to allow for the lead resistance as it was to compensate for the battery condition. They don't have a real stable current source (I think it's just a resistor), so the zero would be all over the map.
Something to be aware of with digital units is that the "continuity" or "diode check" scale is NOT a resistance measurement! It actually displays VOLTS, not OHMS. The reason for this is that a good diode has a forward bias voltage of around 0.7 volts. A lot of folks use the diode check range, see a reading of less than 1.0 and assume the resistance is zero. NOT SO! When in doubt, double-check the actual resistance.
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Today's Featured Article - Harvestin Hay: The Early Years (Part 2) - by Pat Browning. The summer of 1950 was the start of a new era in farming for our family. I was thirteen, and Kathy (my oldest sister) was seven. At this age, I believed tractor farming was the only way, hot stuff -- and given a chance I probably would have used the tractor, Dad's first, a 1936 Model "A" John Deere, to go bring in the cows! And I think Dad was ready for some automation too. And so it was that we acquired a good, used J. I. Case, wire tie hay baler. In addition to a person to drive th
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