Doesn't seem to be that many dead trigger issues but I still wanted to post this, along with the cause/fix for anyone who may experience this problem.
Last time at the range with the Spectrum I had a few instances of the trigger not engaging the striker on a first pull. It only happened with the first round after dropping the slide from a full mag, but would always reset and worked normal on the second trigger pull. Since I fired more than 100 rounds and it only happened a few times I wasn't too concerned but did wonder what's going on with it. A search of TA only turned up one other instance of a dead trigger issue, and that was posted by BigAl512 in this thread. His seemed to work itself out and no more was said about the problem, however I have my theory as to why Al's worked itself out which I will say later.
So the other day I pulled out the Spectrum and got to looking at it. After messing with it for a while I found the dead trigger was only happening after dropping the slide using the stop lever. Racking the slide by the sling-shot method wouldn't cause the problem. Didn't take too long to duplicate the issue over and over and quickly discover the cause. Dropped the slide using the slide stop a few times, field-stripped the pistol and there it was, the trigger bar remained in the disconnect (down) position. What caused this was that the trigger bar was being pinched between the chassis and frame and wouldn't return to the up position until the trigger was pulled or I applied pressure, pushing the chassis back to the left.
Although the chassis fits snug in the frame (fore and aft), the back of the chassis has about .030" left/right play where it locks into the back of the frame. When the chassis has pressure applied to the right, as in the case of pushing hard on the slide stop, it will move just enough to pinch and hold the trigger bar in the disconnect position.
Picture 1- This is showing where the binding is happening.
Picture 2- The arrow is pointing at the tab of the trigger bar which contacts the striker. In this case you can see the bar is in the disconnect position, below where it will engage the striker. There should be no reason why the return spring wouldn't have the trigger bar in the up position with the slide removed unless it's binding.
Picture 3- Arrow is pointing to scratches where the trigger bar's sharp (stamped) edge had contacted the frame. This is where I believe BigAl's dead trigger problem worked itself out. If the trigger bar scratches the frame enough times it might just wear the plastic and relieve the bind. I had polished all the edges of my Spectrum's trigger bar when it was new so mine probably wouldn't have worked itself out.
Picture 4- My simple fix. Cleaned the tab at the back of the chassis and added a dab of RTV on each side so it will have a better (snug) fit into the frame. Once the RTV cured I reassembled the Spectrum and can no longer duplicate the dead trigger. I haven't been back to the range with it since the fix but am confident that it won't fail again.