Badger,
Can you tell us what kind of soldering iron you’re using as well as what kind of solder? I am looking at the build and only see a few “really good looking” solder joints. If you’re using the cheapest Weller soldering iron from Home Depot with no temperature control and/or using anything but 63/37 or 60/40 rosin core solder (rosin is the flux), then you’re going to have lots of issues. Each of your solder joints should be shiny and Hershey kiss shaped (or slightly elongated Hershey kiss shaped).
There are a bunch of soldering tutorials on YouTube. https://www.youtube.com/watch?v=AqvHogekDI4 is a decent one I just viewed. You can use a tip like he does if you like, but many people prefer a sharp conical tip (not a stubby pencil tip either). I like this video because it shows the “capillary action” of the solder sucking into the hole on the board, which many videos don’t show.
Temperature controlled soldering irons start at like $12 on Amazon, but I recommend you find one that has a decent stand so you don’t burn yourself or your table and perhaps has a decent sponge. Probably $40. It doesn’t have to have a digital display for the temperature, but a lot of inexpensive ones do have this now. Almost all of these accept the Hakko-style tips, which is what you want.
If you already have a decent soldering iron, then I think the solder itself may be the issue. Definitely don’t use silver solder.
I’ll reply back to your email again tomorrow and discuss replacement of your circuit board, etc. (I’m going to bed now)
Best Regards,
Bruce
Pedal Parts and Kits