Ok, this one's a real quickie. One of the guitarists in my band got this wah (Dunlop ZW45 Zakk Wylde Cry Baby Wah) as a gift a number of years ago, and in the last few weeks it developed crackly and intermittent sound (regardless of being on or off).
Initial fiddling with the power / input / output jacks pointed towards a questionable patch-cable, but even that soon stopped working, which then turned my suspicions towards cracked solder joints (rather than the jack sockets themselves).