Take the salmon out. Like Walt, smoking salmon at 190 (I use 180) usually takes less than an hour (or up to 1.5 hours depending on thickness, etc.) to reach 135 internal temperature. If you are going on 3 hours...it's more than done! Your probe sounds correct... registering the internal temp at 150 after 45 minutes smoking at 190. First of all, 150 IT is too high. What is your judgement of "raw"? Everyone has ideas of what "cooked" salmon is. 135 is my recommended temp, but I often go only to 130. It might seem raw, but salmon will continue to cook after you remove it. Take it out, let it rest. If after resting, if it still seems raw, it's got enough smoke. You can add cook to it by putting back in the smoker, or putting in the oven, or in a pan. But I'd be surprised if it didn't flake without additional cooking. Properly cooked salmon should just barely "flake", and should be soft and juicy, not firm.