Hello -- I'm so happy to find this forum!! I've been working on my K100-2. A mouse (or mice) built a nasty nest inside and the amp developed a very loud hissing sound that would get louder as I turned up the volume control. All the other functions worked as did the reverb and trem. The hiss, however, is SO LOUD that the amp was unusable. I traced the sound, using a signal tracer that I built, to the very front section of the amp, the pre-amp. In the process of replacing pre-amp transistors, I managed to break the leads of the 3754 (which was clipped to the chassis) right at the base of the diode. I've ordered another, which hasn't arrived yet. When it does arrive, I want to be sure that I hook it up the right way. Don't want to reverse the polarity. Unfortunately, the way the leads broke, I can't tell the way the original was hooked up.