On some occasions performing a hard reset can solve issues with the ISA units.
To perform a reset follow the below steps.
- Hold the 'Clock Select' & 'Ext Sync' black buttons on the right side of the ISA unit.
- ISA Two: hold down the 'Z In' and 'Input' buttons on the very left of the unit instead.
- While still holding the buttons, power off the unit using the power switch.
- While still holding the buttons, power the unit back on using the power switch.
- Wait for a few seconds, release all buttons.
- Test again.