Poison Apple Auto-Wah is my third pedal. After hooking up the battery, IC4 (L78L05) blew out. Measuring voltage on pins one and three of the Ic4, I have about 8v. Pin one should have 5v coming out of it. Looking at the schematic, D4 (1n4004) would have 9v landing on pin one. I looks like D4 is...