(thanks for the input)
Point by point:
1, power supply is clean and pretty well decoupled

2,the false capture is occurring on the 'wrong' edge. If I select rising edge trigger, I sometiems get falling edges AND vice versa....

3, I am already doing the pin toggle thing. I have not found anything suspicious with the scope (dangit)

4,Have done this, the software is pretty clean
and performs flawlessly in dScope. The fact that the false trigger is 'exactly' co-incident with the wrong edge and my RPM calculation jumps to exactly double leads me back to the hardware.

5, I may try the 2701.

6,7, Going to have to try Klepto. Visio seems like a 'fixed' Coreldraw. I have it on my other 'puter.

8, in 1994 I built the laser cutting machine that puts the molding attachment holes into the Sunfire/Cavalier (I think 2003 is the last year they are using it) Convergent Energy (the old Coherent General) lasers + robots. I haven't fiddled with lasers in about 6 years. Got wound up in software employment and consulting.

Regards,

Bob
I will let you know what/if I find the problem. The software work-around is currently working well.... (just bugs me)