Just about everything. It takes 3-4 tries to turn it on or off, then it pops and hisses. If it does work, the signal cuts in and out, while continuing to hiss. He tried to have another pedal maker fix it, but he couldn't. It's as if it sustained physical or water damage.
Ah I see. Well that sucks. What a great pedal to have had it die that way. You still have a grand little board there!