of course there is a GAL16v8,which produce up/down and clock signals from AB signals from encoder
Does it
1) synchronize the input (2 d F/Fs that must be identical for each channel to make the signal move forward.
2) base the up/down on previous and current state.
3) do you have schmitt triggers on the encoder inputs
4) is the inverter drive and the encoder logic on the same board

the counter is functioning very well without a noise source the problem is when i want to drive a motor with an inverter the counting flip flops in 4029 chips are set randomly all of a sudden without a count pulse from encoder

Have you tested whether the real statement is 'mptor running' or 'inverter active'?

Erik