Reply To: Help with green LEDs being skipped

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Windell Oskay

First, I would urge you to be more careful with “resoldering” type work, as it is often possible to cause problems by resoldering or overheating things that don’t need to be soldered.

The 9 LEDs that are affected are (reading out the names from the green green board) D39, D93, D49, D94, D19, D91, D29, and D92. You can see how these are wired up if you refer to the schematic.

The two other LEDs connected to these are D59 and D95, located above D46 and D56, respectively. You may also see an issue present on those two, if you look carefully.

These 10 LEDs are the only 10 connected to the “LED9” signal. The first thing that you should check is the soldering on the “LED9” vertical jumper, and at resistor R9. You might check with your multimeter that there is 24 ohms of resistance between R9 (measured on the green board, or at any of the affected green LEDs) and pin 5 of the microcontroller. (Pin 5 is close to the rectangular outline at J2.)

Carefully inspect the soldering at all 10 of the affected LEDs. If you have the ability to, test the LEDs individually as well. A failure of any of these LEDs — due to overheating during soldering or bending stress — could result in what you’re seeing.