I just completed my first pedal mod that actually changed what the pedal does! And because I'm just a big enough geek about it I need to share with everyone.
Inside of an old DOD FX-75B are three trimpots used by the factory to dial in the exact settings of the pedal; labeled P1, P2, and P3. P1 is a suck knob if you mess with it. Too much one way or the other and it pretty much kills the effect. I believe (based on a suggestion from niftydog months ago) that it is used to bias the bucket brigade chip. P2 and P3 are not suck knobs. I am not certain what they do but they are very interactive and together intensify or reduce the effect dramatically. For my mod I cranked the P2 all the way to its' most extreme setting and replaced P3 with an external pot. I can still get pretty traditional and subtle flanger sounds, but I can also get really wild whacked out sounds and also some self ocsillation.
Here's a clip and here's a pic. The flanger can get more subtle than the clip indicates, but I just took it down to 'thick flanger' sound for the sake of a shorter clip.
