The chain of stupid mistakes continues. The new boards arrived shortly before Christmas, but I didn't have more HT16K33 chips to test them. Today, after a month on the way, the chips finally arrived. Of course, because I put the chip on the bottom layer this time, I mirrored the footprint and all the pins are wrong. I soldered two boards before I realized (because I wanted to make sure it's not a faulty chip). When I realized it's the PCBs that are wrong, not the chips, I decided to recover them. I don't have a hot air gun at home, so I went for the hot-plate approach. First, I removed the plastic from the pin headers, and desoldered each pin. Then I turned on my electric kitchen stove, waited a bit until it became hot, placed a board chip-up on the plate, and pulled with tweezers on the chip. At some point it just came off. I repeated the same with the second board, and even got the SMD resistors back.

Then it's back to the drawing board. I re-did all the connections the correct way, and ordered the boards again. See you in a few weeks when they arrive.

This was really supposed to be a short and simple project...