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Auto-ranging

By Ian Enderwick, Ontario Canada

While I was working as a two way radio technician, my shop had one portable radio that no one could repair - it was stuck in transmit. To make it transmit, one lead had to be grounded, but no one could find where it was grounded. I checked it with my Fluke 83 DMM in Ohms auto-range, and it was shorted to ground by 120K ohms. No other tech had an auto-range meter. They all selected the low ohms (<400 ohms) thinking that they could find the short to ground. I traced it to a shorted SMT capacitor, which I replaced and finished the repair. After that, they all saw the value of a better meter particularly with auto-ranging capability. The auto ranging allows you to keep an open mind, by not presuming what the problem is and let the meter do the work for you.