I have a friend in Mich. that just restored some L220's and he he is having problems with his midrange level adjustment pot smoking, at high power levels. I have told him about the contact cleaner thing and before that I told him to do the back and forth trick to maybe clean the wipers in the pot but it is past that point as Smoke is coming out now!. Does someone know if the tweeter level control pot from an L19 will work in it's place? I have a pair of crossovers from them and they look the same size but wonder about other factors. I would appreciate any advice. Thanks, Steve G