Hi all, Returning player and keen to get my trumpet running smoothly. It's a Yamaha YTR4320, plenty good enough for me I think. The tuning slide is pretty stuck and on both sides. 1st valve slide is good, but 2nd and 3rd won't budge. All the valves are good. I've never done any trumpet maintenance but i'm on a budget. Is this something I can fix myself, or would you recommend getting a professional to do this? I'm not sure what the trumpet is worth, but I guess that should be considered before splashing out on some repair work. Pics below (i hope). Any advice much appreciated!