Almost done, and I have confirmed the above behavior–all LEDs work, the sketches run as they should, but Row 1 LEDs light when any LED from the same column is lit. Row 1 is very bright compared to the others. Checked transistor Q1, and I see nothing visibly wrong with it. Checked the soldering on U2 and it looks OK. Could I have a damaged transistor, or should I look elsewhere? Thanks!