Hello colleagues and happy holidays. Last week I got three pieces that I was missing in my collection for a great price, MK18-X650 and the regulator that I like the most and that has cost me the most to get, the G250V. The seller assures me that he had just serviced all three. I started with the G250V, all the pieces were embedded, after going through the ultrasound machine I can disassemble everything except the tube, the nut shows signs of having been forced with an incorrect tool, I have tried ultrasound, hot-cold, white vinegar -water at 50% and at the end wd-40 and 24 hours of rest and nothing, there is no way. In the end I gave up for fear of damaging the box, since I noticed a little looseness due to the force applied by the previous crank. In the end I cleaned it, changed the kit and tuned it, but the nut does not come off and I like to be able to disassemble it by I complete all my regulators. ANY MORE IDEAS WITH THE DAMN NUT? Thanks and regards