radiophonic Posted July 9, 2020 Share Posted July 9, 2020 I need to get into the wiring of my Mexican P-Bass but the grub screw on the tone pot is totally seized so I can't get the scratch plate off. It looks like it's a brass grub with a flat head. The one on the volume pot was very stiff but GT85 and some patience eventually freed it up. I have a small blowtorch, but I'm a bit wary of the heat method as I don't want it conducting into the pot wiring. I'm starting to think that drilling it out is the only option but I'm open to less destructive suggestions if anyone has anything to offer. Quote Link to comment Share on other sites More sharing options...
hooky_lowdown Posted July 9, 2020 Share Posted July 9, 2020 WD40 👍 Quote Link to comment Share on other sites More sharing options...
PaulThePlug Posted July 9, 2020 Share Posted July 9, 2020 (edited) try plusgas... penetrating oil... wd40 is a water dispersant or fine lube... not as good as plusgas. same as bike maint... drill it out... sometimes even with a normal drill, on reverse, may have enough bite to remove... maybe enough to just replace the set screw... rather than the knob Edited July 9, 2020 by PaulThePlug Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted July 13, 2020 Share Posted July 13, 2020 Get an old fuse screwdriver and heat the tip to red hot and hold it against the grub screw. being brass it should quickly conduct the heat and expand, which - in theory - should break the grip of the crud, thread lock, or gunk that's seizing it. You might have to do it more than once. If there's enough of a slot left it also sometimes helps if you turn it slightly to tighten it before trying to unscrew it. Brass is soft, so don't overdo this if you give it a go. Quote Link to comment Share on other sites More sharing options...
Woodinblack Posted July 13, 2020 Share Posted July 13, 2020 Just to be the one to ask the really dumb questions but.. why does the tone knob being stuck on stop you getting to the wiring? The tone pot is bolted to the scratchplate(*) so when you undo the screws holding the scratchplate to the bass, you can just turn the scratchplate over and there is the wiring. You don't need to take either pot off. Or am I missing something? * official BC determined term Quote Link to comment Share on other sites More sharing options...
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