Did you talk with Bill or Tony?
I have a 12 year old SM150, my thermostat went out. I ordered one from Cookshack it arrived yesterday. They sent me item PV721 cost about $215. Problem was I set smoker to 250 but the display never showed above 120 but I heard a sizzle so I put a probe down the top to check temp was actually 297 my poor ribs : (
I hope to install it this weekend and that it will fix this problem.