It seems odd that it would work with a single short slot but not with a series of them. This might indicate a problem with the driver circuit, maybe a too-weak pull-up.
It might be worth tracing the circuit on that board to see if it makes sense, but getting the component values might be hard, unless the markings are still visible? (SMT caps seem to often be unmarked)
russkinch wrote: i am running the sensors with an external 5v power supply, not from the pc motherboard like i have read some do.
Ah! Don't do that
The encoder pulse signal needs to be referenced to the same 0V as the parallel port. All bets are off if the opto is powered from a separate floating supply.
Chop the end off of a USB cable and use the red and black wires for the 5V then connect that to the control PC. You might well find that everything suddenly works an awful lot better.
russkinch wrote: A phase on hal scope is flat line. Index is multiple square lines (good).
Is the Halscope running in the base thread or the servo thread?
Is the A-phase a flat line at all spindle speeds or only when above 275 rpm?
Is there any evidence that the A-phase has ever worked?
Are you using M3 or M4 to start the spindle?
I was doing some other digging on hal meter. spindle-cmd-rps gives a negative number and spindle-cmd-rps-abs gives a positive.
That sounds correct, allowing for reading it by eye.
spindle-velocity-feedback-rps says 4.53..... but rpm says 275.