Hey Everyone,

I know this likely means I missed a soldering point, however I was wondering if anyone knew which soldering points I should be looking at when the Fourth Row from the bottom of Green LED's stays dark.

Thanks so much!

Meggy Jr RGB, right? Can you say what row it is, using the numbering scheme on page 9 of the programming guide? (Row 3?)

Yep, its the Meggy Jr RGB. And yes it's the Row 3 when looking at the code for it. The Red and the Blue LEDs for that row work fine but the Green LEDs aren't working. I was checking all my soldering points and couldn't find one that was suspicious looking so I was wondering if you might know which ones drive that particular set.

So after a couple hours of staring at the schematic I fixed it up. It was of course a poorly soldered connection. I traced it from pin 23 on the LED Matrix in U4 back to Q3 and then to pin 11 on the ATmega328. After that it was still not fixed so after soldering U3 no luck, but after soldering U2 its all chipper and working beautifully.

I still don't understand why or which pin it was on U2 that was acting up but if any of you have some theories I'd like to hear them.

Hi Chris,
I'm glad that you got it working-- although you seem to have beaten me to the solution.

The LED matrix sits sideways on the Meggy Jr RGB, and what we call row 3 is actually column 5 according to its datasheet-- its columns are numbered 1 to 8, looking at the matrix from the side with the label. From the schematic, Col5Green on the matrix is connected to signal Col11, which connects to pin 16 of U2.