( Solved ) Mesa 7i76 encoder problem

I have a 5i25-7i76 that has been working fine for a few years on a small lathe.

The encoder is a home made disk with 3 slot sensors A+B+Z fed into the TB-3 encoder single ended. The spindle speed has stopped displaying

I have put a scope on the A,B,Z pins on the encoder on TB-3 . They are showing that the square wave pulses are fine including index

I am thinking that the board has gone faulty. I don't need the B pulse so as a test could is it possible to change the firmware so that Z is put on to B. Or could the - Z be used.

If you look at the encoder connection in hal meter can you get the leds to change state?

OT-CNC wrote:

If you look at the encoder connection in hal meter can you get the leds to change state?

only A and B not Z I also don't get a count on Z or any of the things like revs etc

tommylight wrote:

Did you check the enc-a, enc-b and enc-x with hal show ?

Yes Tom it is the index that is not working Ie no counts or revs etc

The index input can clear the count but that's it

Did you check the encoder input-a,input-b and input-index pins in hal?

PCW wrote:

The index input can clear the count but that's it

Did you check the encoder input-a,input-b and input-index pins in hal?

Thanks Peter. This has been running fine for a few years I have not modified any of the files It seems to have just died.
they are wired single ended.

I can see the square wave of all three with a scope. I can see the Z pulse with the scope

Is there a way to prove the Z pulse is working on the TB-3 encoder the spindle speed displays 0 in the pypvc panel

The spindle speed is not affected by Z, only A of B
Can you check the input-a, input-b and input-index pins in hal?

PCW wrote:

The spindle speed is not affected by Z, only A of B
Can you check the input-a, input-b and input-index pins in hal?

Do you mean in hal show of the hal file itself

in halshow or halscope when linuxcnc is running