This Phase 90 came D.O.A. It did not power with batteries and/or power supplies. I got to work opening it up and checking out the guts. The obvious part the look at first was around the power jack(filtering and protection). Lo and behold, the Zener protection diode was shut(shorted), sending all voltage to ground. The correct replacement was a 15v Zener diode(1N4744). I didn’t have one available so I had to order a few. I could have used a 12v Zener but that would have limited the use of the pedal since it can be used safely with a 12v power supply for ‘higher headroom’. It could have been used without the Zener too, but if the same thing were to happen again the damage would be greater and harder/more expensive to repair.  After a couple of days the replacement component came trough the mail. I soldered it into place and proceeded to plug it up and give it a try. It powered up but no sound! I had adjust the internal trimpot to get a phasing sound out of it. It turned out perfect! I put it all back together into the enclosure, and its owner picked it up the very same day it was done.

Pictures time!