I use to do this a lot but it been over 8 yrs since I did the last one So I am very rusty on it. But can atest how hard they are to reset off the saw. Even the one that give copies from the service I end making a reset tool to fit it so I could use a pull bar.
I do know the handle should spring forward on a properly assemble unit or at least the new OEM one I have here does.
I seem to remember that handle spring has to left out until the knee joint is set and then put back in so the handle will spring forward but as I said the cobwebs are in the way.