Crackly when tone high

[kerley]

Got a Yamaha RBX a few months back. Was a bit hummy but easily removed just by shielding. Until last week was totally quiet.
Then last week the blend pot went a bit strange and whilst still working only made a difference in the first 1-2mm of off centre position, the rest of the turn made no difference. And also started to get some crackle at the same time so had to roll tone almost completely off to remove it (also went away a bit when touching bridge,strings etc,)

Replaced the blend pot this weekend and although the blend is now better I still have very bad crackle if tone anything above 1/4 of the way up. (crackle gets louder as tone goes up) This is not just annoying background noise, this makes the tone unusable.

Anyone any ideas what could have suddenly gone wrong to have caused this? (all the wiring feels okay but I will double check it all again today.) Could it be one of the other pots or is this not a symptom of a dodgy pot?

Edited June 7, 2009 by kerley

[BOD2]

Is this an active bass ? If so, try changing the battery.

If not, or if a battery change doesn't work, it's worth trying to squirt a contact cleaner into the inside of the noisy pot. A squirt of "Super Servisol" or equivalent, into the workings of the pot will often help.

[kerley]

Having messed around with it yesterday seems like an earthing problem as noise goes away when pressing pretty much anything (pots, shielding etc,) with a screwdriver. Not sure how that could suddenly happen but I have started a bit of a rewiring project (to the point where I have run out of solder so need to continue tonight after buying more!)
Thanks for the advice anyway.