Installing the stabilization fix I was very cautious and it went fine until I finished the install. One last step, and when snipping the excess tie-end off, my wire cutter catches the top corner of Q5 and the transistor body snapped off the metal tab. I didn't even know I did it until I start playing and one of the coils doesn't function.
Fortunately that's a serviceable part. Does anyone know if there's other reasonable substitute for PSNM027 / STP40NF10L? I have a bunch of other pinball transistors. Would IRL540 do? I guess it's 28A vs 40A. Just wondering if that high is actually necessary.
Found specs for IRL540N which I have. It sounds very close, I will try it:
Yes, IRL540N installed and works fine.