Firmware retract with Marlin

Hi,
Can someone please help me to get the firmware retract to work. I have a Velleman K8200, running Marlin V1, Repetier V1.0.6, Slic3r 1.1.7 and want to use the Firmware Retraction.
I have sent M207 S1 F25 and M209 S F25 to set up the retract/unretract. The gcode correctly has the G10 Retract and G11 Unretract, but I get no response.
Any suggestions?

Wally

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To get the right answer, you must ask the right question!

I have the same problem with Marlin and K8200 & Arduino Mega-Ramps1.4 - The retraction just does not work without any apparent reason.

Eventually I got the retraction to work, by uncommenting the FWRETRACT in Configuration_adv.h (followed [prusaprinters.org]), only to discover that the z-axis lifts on every retraction of the extruder, even in mid-layer!

I cannot find the cause of this or how to correct it, any suggestions? I have tried sending M207 S0, but it does not help.

Wally

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To get the right answer, you must ask the right question!

There is a configuration in Slic3r to lift the Z height on retract. This is supposed to help with dragging the nozzle / leaking plastic through the print. Should be near the retract settings.

The problem was that the Z would lift every time the extruded retracted (even with manual retract), but would not go down again on unretract
Eventually, the problem was solved by sending M207 S0 Z0 & M208 S0 Z0 manually. There must have been a value stored for Z, probably when killing a print, which was cleared this way.
Hope that this will be useful to someone.
Wally

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To get the right answer, you must ask the right question!