new mendel, no z axis movement

Hi, my first ever build and I'm stumped on testing. I have x and y movement, but the z motors just make the vertical threads vibrate. They don't turn.
I've checked the wiring and terminals for the motor and end stop.
The threads turn easily by hand.

Where next?
Does the potentiometer for the two z motors need to be higher?

Ok further information. I swapped the X and Z wires at the control board, and can move the Z axis fine using the X controls of pronterface, and the X motor does the same feable vibrations as Z motors were before.

According to my build instructions, I should turn the pots on the control board until I get 0.4v across the cap of the pot and power-in-gnd. I can get the X, Y and extruder all to this, but the Z is always reading zero!

sounds like a dodgy driver chip

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Experimenting in 3D in New Zealand

Ok thanks. I've contacted reprappro where I bought the kit explaining the issue. I'm hoping they weill replace it under warranty!

You could try turning the post up it doesn't need much

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__________________________________________________________________________
Experimenting in 3D in New Zealand

Yeah tried this, but it makes no difference and still read zero volts on the pot regardless of how far it's turned.

Probably a short to ground on the PCB, missing series resistor, or a duff pot.

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