with nothing in the OBEL, that side of the switch will also render the guitar inop. so ensure you try both sides of the switch. i'd reflow all your solder joints. also make sure the out put jack is not touching anything in that cavity since you have the shielding in there. electrical tape along the wall the jack may be hitting will insulate things. i'd also insulate underneath the buffer the same way.
if these do not work, bypass the buffer by removing it's input(blue) and output(yellow) wires and soldering the extended wires you have to them together. if this works then it is the buffer, and we will deal with that. looks like you have one of the early handmade PCB versions, VINTAGE! Lol.
Disclaimer: I make and sell Buffers. I also sometimes Modify, Build and sell preamps and amplifiers. My opinions are not intended to be sales pitches. I am a one man shop and prefer to spend time with my wife and family, i work full time on call and love to spend my spare time doing other things. I only make, modify or build things for those that seek them.