could be anything almost… if there’s no led or anything it sounds like there’s no power, have you checked the battery snap is connected and not broken or anything? battery good?

if you want open it up and see if there’s any wires disconnected, post some pictures if you can, we might be able to see something.

This is just a long shot, but if I’m right you can refer to me as a genius. I have picked up a plethora of the old DOD pedals, and many were non-functioning in the same manner. Often, but not always, it turned out to be a J201 FET at the input (part of the buffer). My only guess is that someone put the pedal further down the line and fed it a hot enough signal that it overloaded the JFET and it gave up. That’s probably wrong, as I can’t see a signal that big coming in, but it was still the J201 more than a few times.
A quick check, and the schematic is available online. The power comes through a J113; check it. After that, scope it through the signal path, and you’ll likely find it sooner or later.