z wobble wavy

so, have 2 deltas, one prints good, other has this z shift / wobble. i tried new power supply, pid. what could it be. i tried tightening the frame parts...

electronics board maybe?

is this a Kossel style delta, ie with 2020 aluminium extrusion uprights and rollers along the extrusion

If so so a few moves from xyz=0 to xy=0 z=max and back again and watch the nozzle does it appear to snake side to side as it moves?

also take a look at the carraiges as they move up and down do they all track straight or do they have a wobble?

Finally look at all your rollers, do these ALL track straight?

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

found out the issue, it was a sticking wheel, replaced and now good