got a reading of .4 on all 5 -
The nominal 0.6 ohm (cold, but not too cold) value of the new-style plugs is in the borderline area of being able to use a garden-variety ohmmeter to diagnose. Consider the lowly series plug of yore, that has a nominal (hot) resistance of 0.02 ohms, probably half that when cold. That's why you use a voltmeter in-circuit to diagnose those, there's hardly an ohmmeter alive that can give you that number meaningfully. But fed 50A of current and the nominal 1V dropped across it is well within the good range of a standard voltmeter. In effect you're using the remainder of that GP system as a dummy load for the DUT. No such luck on the parallel system, you need a hefty series (or clamp-on) DC ammeter to diagnose those, if the ohmmeter doesn't cut it. Another idea would be to keep around an old series GP for use as a shunt for measuring heavy current. It would drop 1-2V feeding a new-style GP. A little bit of calibration work with a known good plug or two and you'd have a cheap (and small) test harness for GP's. Just don't burn yourself! -- Jim
