EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: lern01 on November 25, 2024, 12:15:58 pm
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A Fluke 287 was powered by a maintenance power supply. After the logo appeared when it was turned on, the current suddenly increased to about 200mA, and the screen went black (probably because the 287 automatically shut down for protection). The case was opened, and the voltages of each line were checked. There was no 5V voltage. The 5V power supply terminal of the 287 was checked with the diode range of a digital multimeter when the power was turned off, and a short circuit to the ground was found. The machine was baked using an external power supply of 2V and an overcurrent protection setting of about 800mA. When it was added to the 5V terminal of the 287, U9 immediately became hot and a little hot to the touch. The IC was removed and the power pin and the ground pin were short-circuited. After replacement, the machine started up normally. The machine was perfectly repaired.