Fluke 289 Repair Leads connected incorrectly

Описание к видео Fluke 289 Repair Leads connected incorrectly

Fluke 289 multi-meters seem to be prone to problems with the test lead detection system. I have repaired 3 meters so far. The simple system consists of an infrared LED that flashes, and the flashes are detected by sensors on either of the current measurement jacks. If one of the jacks has a test lead plugged in, the IR LED signal is blocked and the meter registers that a lead is present in the current measuring jack. If the meter is set to measure something other than current (ie, voltage) then it will give the error that the leads are not connected incorrectly. In this video I show a meter that gives the error that leads are not connected correctly, even though there are no leads present. The meter "thinks" that there is a lead in the current measure jack, meaning it does not see the IR LED signal. Previously, this was because the LED had come off of the circuit board, however in this meter, the error was exasperated in a bright IR environment, like sunlight. I am not sure exactly why this meter behaved this way, however simply melting the solder (reflow) on the two pads that connect one of the IR sensors fixed the problem. After this video I went back and reflowed the pads for the LED and the 2nd sensor.

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