I have a similar problem as one of the others. My 3rd row started showing Red when the Blue was on. I got a good Red and Green, but Total red. I have cleaned everything and got it to be blue-ish, but I can still tell there is some red in it. I checked everything, following the Row 3, but I cant see anything.
Could you post a picture of the fault to this thread (via the insert/edit image button I just added) showing the board with all columns and rows in blue? A picture of the back of the board in as high resolution as you can get would also help.
A copy-paste of your void(loop) would also help.
A mixture of red and blue is strange, as they are on different shift registers and the red and blue pins on the LEDs are the two furthest from each other. This will be an interesting problem to solve I’m sure.
I have got it to where they are less noticeable. I have also moved on to get all 4 boards together. I cleaned up every joint by touching it again and useing a magnifying glass for the joints,. and I still couldnt find why.
Thank you and If I need more input Ill let you know.