Things were going so well tinkering around with my Electromatic 5420T. First the harness out and some changes, setting up neck, new strings and set up pickups. All fine until the last tweak on the neck pickup height adjuster screw which suddenly locked up and will not budge. The other 2 adjuster screws and springs work fine but the top adjuster screw towards the neck circled in red is stuck solid. I released the tension on the other screws but no movement. I managed to fish the neck pickup out and can’t see any problem, there is a small amount of slack in the spring so its not overtightened. I could be more forceful on the screw with the pickup out of the guitar but no joy although I did managed to pretty much round off the Phillips head! Also tried trying to turn the end of the screw with pliers and a bit of lube on the thread but it will not move. I am puzzled about this but want to get it back to being adjustable. I like the Blacktops so not tempted with an alternative and it would be crazy if it can’t be fixed. Do any of you learned people out there know the screw thread, length and spring size of the adjuster, if the size I am looking for is metric or imperial and if you can get replacements for the Balcktop chrome Filtertrons? As mentioned the guitar is an Electromatic 5420T year 2011. I have seen adjuster screws and springs for Humbucker pickups and the screws seem generic although the springs differ in build and size would something like that work, if so any recommendations? If I can get replacement screws and springs I can remove the pickup and try releasing the offending screw in a vice with a bit of WD40. I’m not looking forward to gemoving everything to get the pickup out but needs must. This problem has made me seriously consider pickup connectors and I’ve just put the harness back..... Any help and advice would be gratefully received.