Geeetech

OK, I've soldered all the connections, just in case it makes a difference. Basically, I'm clutching at straws at the moment, trying anything & everything to get my 3D-Touch working properly... Naturally, I'll post the results back here.

They will improve the product, I believe in the near future this problem can be fixed

it dropped less. I only counted it dropping once during my last print, but I might have missed some. It's still not right though.

I walked away & left it printing, rather stupidly. Pin dropped again, after about an hour of my 5 hour run, caught on the print & mangled everything. I now have to go back, re-calibrate everything again & check to see what, if anything, got bent or broken in the carnage. Thankfully, it was only left unattended for 10 minutes or so, so it could have been so much worse.

For the record, the pin dropped again, completely destroyed the print & threw out the calibration on my printer - again.

This is the advice that I have been following on getting the grub screw correctly positioned:
https://www.youtube.com/watch?v=Ix7lXvfkPEU

It gives this text as part of the video:

if there is an alarm, use scrip 4: M280 P0 S160 to release alarm first. then use a screw driver to turn the screw in the top of the sensor, when you turn anticlockwise, the pin will be retracted a bit , keep turning the screw until the LED turns off. at this time, when you turn the screw clockwise, the LED will light up again, that is the critical point, if you find this point, the LED will be normally on, meaning it is normal now.

This is what I've have been repeatedly doing, although it is interesting to note that one of the posters in the comments section had an identical problem to mine, with the pin dropping. He didn't say if he ever fixed it though...

You can contact the related sales for send you a new one

Thanks William, Charly Pan's already on the case. We're just waiting for Geeetech Tech Support to help us decide if anything else needs replacing, & then he'll post me out a package. At the moment, I'm taping the pin up with masking tape in the 2 second gap after it finishes auto-levelling & before it starts printing. Whilst far from ideal, it is buying me time.

I have the same problem, it looks as if the platform get accelerated the pin drops, it occasionally pulls up again, but at that stage ruins the print sometimes after hours of printing !!

Just a tip for this issue. If you remove the grub screw then take out the pin and magnetise both the pin and the grub screw by rubbing them on a magnet it will fix the issue. After they are magnetised uses the method above for resetting the grub screw position.

I had this problem too.
I have a Geeetech A30 but built a new controller Box with RAMPS and Marlin inside, because Smartto Firmware sucked.
But the problem is the same. I used the 20 pol cable for the 3D touch/BL touch sensor also like in the original version.
After a while of printing or only staying (with hotend heater turned on) the pin drops.

I have read a lot in the internet some say, firmware issue, some solved it with turning the top screw of the sensor in CCW direction one half or one turn to adjust some eletronic hall effect or so.

But for me nothing solved the issue.

Then I found out when the hotend heater stays off the pin never drops, when it stays on the pin drops after some minutes.

My conclusion is that current for the heater is inducing some disrupance in the signal cable for the servo. Because the wires are together in one line. So signal cable for Servo is beside the heater cable.

My solution is that after the print starts I disconnect physically the signal for the servo at the controller board.
The printer is printing for two hours now without any pin drop.