All 4 PCBs are soldered and assembled!! I soldered and fixed all of them the day before, but then I started facing some problems while testing them.When I tested them individually, 3 out of 4 PCBs were working fine. But 2 of them had the same issue in subtraction mode and were not doing the subtraction properly. At first, everything seemed fine when I tested them individually, so I thought maybe it was a power supply issue. The 4th PCB also had some problems, so I tried fixing that too.I also spent around 4 extra hours soldering, fixing and troubleshooting all these PCBs. This time wasnt included in my original time tracking, so Im adding it here in the devlog.Heres the timelapse of the work:https://lapse.hackclub.com/timelapse/ybwchpALz-pzAfter that, I installed the spacers and tried running all 4 PCBs together, but something went wrong and the whole setup wasnt working properly 😭. Even after fixing the individual PCBs and assembling everything, it still didnt work as expected.But today, I finally fixed all the issues and completed the 4-bit adder and subtractor It took quite some time to figure out what was going wrong, but finally got it working!! Now just 4 more PCBs to go