1. Is there a reason you don't just use the built-in 82M98A encoder chip that I assume is still working?
It is still working. Is there any benefit to using ipac2 vs. the 82m98a encoder? Short of gaining an USB port using the ipac.
If the 82M98A encoder is still working, you might as well use it
unless you have backspin problems.
- That said, changing encoders won't help if the problem is slow response in the optical circuits. i.e. Old Happ "green board" optical PCBs can cause backspin problems, but the newer Happ "red board" PCBs will not.
Trying to use the "active low" IPac is more work for no added benefit
and it's even more work if the trackball opto circuits are "active high".
If you decide to use the 82M98A encoder and it's still working properly, you can ignore the rest of this post.
2. Are either of the data lines stuck high or low? (bad opto or wiring)
I think I measured the wires correctly connected to GJQ-2. Red. white, and brown measured +5V.
Sounds like I could be stuck on logic high.
Either the encoder wheel could be in the "Phase 3" position (both data lines high)
or you're testing without the encoder wheel so neither optical path is blocked and both are in the same data state
or the optical circuits are bad and you have stuck data lines.
Try this to confirm if the data lines can change voltage levels:
- If the encoder wheel is in place so it can block/unblock the optical path,
slowly move the encoder wheel and see if the data line voltage goes up/down as you change between phases.
- If the encoder wheel is
not in place so it can block/unblock the optical path, use a thin piece of cardboard to block/unblock the optical path.
If the data lines can change voltage, what are the actual high and low voltage readings? i.e. 0.2v low and 4.4v high.
Scott