mach3 spindle dro not working, spindle speed changing while jogging and running code

i got a strange problem here.The spindle dro is not working in mach3 turn. the index led blinks in the diagnosis screen when moved with hand slowly it means that mach is receiving the index pulse. but why no rpms are show (just 1 is displayed)
The spindle speed is chaning when jogging the z and x of my lathe. Spindle slow downs when axis moves towards the chuck ( same is with both x and z axis). Please suggest. I have tried reinstalling mach3 (2.0somthing version) and changing the debounce and index delay too.

many thanks,
jasminder singh