Z-Probe homing issue with dc42 Hotend Board v2

Firstly let me say that having received dc42's Hotend Board v2 and I am impressed at the whole solution, it I was easy to install and on the whole works great.

However I am having trouble getting Z homing working correctly. I have followed the steps listed here: [miscsolutions.wordpress.com]

After having added my G31 command to my config (G31 Z1.25 P500) I attempt to home Z (or home all) and I get to a certain postition above the bed (Z-Probe reads ~1000) and it stops homing and sets the Z axis to 1.25. This seems great except when I go to Z0 (G1 Z0) I am still miles away from the bed, in fact probably about >1.25 above the bed. the Z-Probe still reads ~1000 at this point. When I manually lower it further I get the readings of 535 then up 0.05 to get 435.

I don't know why it stops early, it's like it stops moving after the Z-Probe first reads ~1000 instead of going down to 565 or wherever it needs to go. Any Ideas guys?

If the probe reads 1000, that means the sensor is saturated by ambient IR and unable to function. I increased the sensitivity a little in the recent batch so they work better on dark targets such as BuildTak, but even so the only time the sensor should saturate is if there is direct bright sunlight reflecting off the bed into the sensor.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].