I’m almost positive that nothing got fried.
Are you saying that it unusually quiet when the effect circuitry is being bypassed and basically off when the effect is engaged until you crank up the volume?
This is a very common occurrence when there is a bad solder joint in the circuit somewhere. Often times, with bad solder joints, the signal can’t quite get through until the volume is cranked up and the signal has enough power to push through the high resistance of the bad joint. Once it pushes through, it often works for a while (even at lower volumes) but eventually cuts out again. I suggest that you re-flow all the solder joints in the analog part of the circuit, but you might as well do the whole board while you are at it. If there is a bad joint one place, there are likely to be others. When i say “re-flow” what I mean is heating up the joint enough to melt the solder so you can touch the solder wire to it. Not to add more solder, but to add more flux, which is incased in the solder wire. The flux is the stuff that boils and smokes when the solder is heated. It helps the solder flow better and most importantly it seals the joint so oxygen can’t penetrate it and cause it to oxidize. Oxidized joints (aka cold solder joints) become brittle and easily crack.
This is why the physical shape of the solder joint is important…when the joint is jagged or has irregular blobs on it, the flux can’t flow properly around the joint to seal it (mostly due to capillary action). Properly shaped solder joints allow solder to easily flow and settle on the surface of the joint, which protects it from oxidation.
Good luck.
-Brach