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Topic: Mode LED mounted backward! (Read 1202 times) previous topic - next topic

Mode LED mounted backward!

Multiple forum topics mention "broken" Mode LEDs.

I fixed mine. The LED was NOT bad -- it was just soldered in backwards. I unsoldered it and reversed it, and now it works.

It looks like the board layout requires that the USB LED be installed in a reverse orientation compared to the others, and on some units like mine the Mode LED is ALSO installed in reverse orientation, which makes it fail.

Ian, you need to have Seeed Studio be especially vigilant about WHICH of the LEDs needs to be installed in reverse orientation. Also, when testing units, the Mode LED needs to be tested to be sure it is not reversed. A quick unpowered LED test can be performed by applying a current-limited voltage across the LEDs and verifying which polarity lights the LEDs. In my case, I used my multimeter "diode test" function, which dimly lit all LEDs, except the Power LED was *really* bright. Having to hold the probes reversed to light the LED indicates an LED installed reversed, which is correct only for the USB LED.

In the future, it would be an easier build if all LEDs were installed with the same physical orientation, to avoid this problem.

Because of the layout causing assembly errors, I suspect there are also units where the USB LED does not light up...