My friends DL4 crapped out on him - out of warranty of course. Line6 has been giving him the run around and are unable to fix it or offer him anything like 1/2 off on a new pedal or something. We are going to try and track down the problem ourselves and need some advice/feedback from those who are familiar with the circuit a little and may have experienced the same problem. It simply won't power up - of course we've already verified the power supply is good. Thanks for your help in advance!