Thank you for the pictures. I don’t know why you said your solder joints “aren’t pretty”. To me, for the most part, they look like the solder joints in the manual. Do you have a very high standard for what solder joints should look like?
Your board is very neat and clean, so that rules out many possibilities of what the problem could be.
Your pedal should only exhibit this behavior when the power is applied and you hold down one of the foot switches. What’s supposed to happen is when you apply power as you hold down the bypass switch for 3 seconds it should toggle the power-on state…either bypassed when powered on or engaged when powered on. Also, with the tap switch…when you hold the tap switch down for 3 seconds while you power it on, the green led should flash the software version. The weird thing is that your pedal is doing both these things while the power is already on. It appears that your pedal is constantly in a state of reset or something.
The first thing to do is re-seat your microcontroller to make sure it’s making good contact with the socket pins. Take it out of the socket and very firmly press it back in until the bottom of the IC is resting on top of the socket.
Also check the voltage of pin 1 of the microcontroller to make sure it is actually staying a 5V at all times.
You can also double check to make sure that the microcontroller pins and all of the pins on the ISP socket don’t have any tiny strands of solder shorting any of the pins together….re-flow them if in doubt.
You can also check to make sure the wiring from the foot switches are not shorting to ground accidentally. Use your multimeter 200 ohm setting (since you don’t have a continuity tester on your meter) to measure the resistance between microcontroller pin 3 and the round pad of the bypass switch port. Also measure across the microcontroller pin 4 and the round pad of the tap switch port. You should get a very, very low resistance…close to 0.
If all these things look good then your microcontroller might need to be re-flashed.
Let me know what you find.
Good luck.
-Brach