My biggest pain was definately the resistor pack - got it slightly misaligned so it had a strong tendency to bridge... I lost count of the solder, measure, touch, desolder cycles But finally got it right. The LEDs were dead easy - a spring loaded vacuum lead sucker seems to be the proper tool (unless you have a proper desoldering station)

The knob stuff was relatively simple, though I got a really really tiny solder whisker going from the +5V pad to the emitter trace keeping the knob LEDs constant on max. Easy fix once found...

What's your knob LED symptoms, always on (max) or always off?

/Michael