I do not think the issue is with the end stop or sensor. As a matter of fact, the sensor does not ever come into play. As stated before, the gantry use to move to the rear till the sensor was triggered then stop. Now it NEVER moves backward. Instead it moves FORWARD to about the middle of the machine, stops there (no sensor to trigger it to stop) and sets a home position in the middle of the machine. Seems to me it is a programming issue in the main control board
If I understand: after reinstalling, the gantry moved to the rear but did not stop.
Now it moves forward to the middle and stops.
I don’t see how it can be a programming issue as it worked before you took the gantry out and now it doesn’t yet the controller code has not changed?
It doesn’t make sense that it moves backward but it also doesn’t make sense it stops?
Is the USB cable disconnected while testing and does this behavior occur after power up?
Currently no matter where the gantry is positioned (even fully forward) it never moves toward the rear at power up. I have tried with and without the USB connected to my computer
@timb12957 it used to work before you took the gantry out right?
Yes It worked correct before gantry was removed. If you read previous posts you can see how the failure began due to the interrupter plate being bent and not entering the sensor, to stop it in the rear most position. It tried to continue backward and what sounded like the belt jumping on the pulley could be heard. Several times I turned the power off, manually pulled the gantry forward, then powered back on. Each time it tried to move to the rear, never stopping until the power was switched off. After this sequence occured about 5 times I discovered and corrected the bent interrupter plate. However without going to the rear, it then began to ONLY move toward the front of the machine during power up.
Overall from the scenario it seems that the sensor or breakout board must be damaged. I have no idea why damaging it would cause the motor to go the wrong direction and stop.
Not sure what to try next but if you have a meter that would allow you to make measurements we can try an measure the sensor while interrupting it. You would have to remove it from its mount?
@donkjr I did have this symptom from the get go with my unit. A bad solder on one of the cables from the mechanical endstop made the motor go and try to home in the other direction. Not sure exactly was the relationship but I have seen other users lately with the same issue
@timb12957 based on @Ariel_Yahni_UniKpty post I would try and ring out or test the signals from the end stop board and verify it was working correctly?
I do have a multi meter and a very basic knowledge of testing circuits. However I do not understand the term “ring out” nor do I know what to look for to test the signals. As well unless I disconnect the stepper motor for the Y axis, even if removed from it’s mount, the end stop would be connected by the cables to the gantry which is in motion making it difficult to test the circuit. Again let me say thanks to all of you guys for not giving up on trying to help me resolve this.
Search for how to test continuity with a multimeter this does not need to be done with the endstop connected. What we want is to make absolutely sure the issue is not the endstop or cabling. BTW I will say that if this machine is under warranty start to include the supplier on the issue just in case you need a replacement part
When I get home this evening I will test for continuity on the end stop sensor. The machine is only 2 mos. old so is still under warranty. I do wonder how much success anyone has had with warranty service with these machines since they are sold by so many different eBay vendors.
If you provide good info and a serious claim they will warrant it
@timb12957 Ok, see if we can do this remotely :).
Check “continuity” on the Y end stop as the first item.
Put your meter on the lowest ohms scale or if you have a mode that lets you get an audible, use it. Verify you are set up correctly by shorting the probes together to get zero ohms and/or a beep.
Use the schematic on this blog post: http://donsthings.blogspot.com/2016/06/k40-optical-endstops.html
Check these traces from connector C10 to their endpoint, per the schematic:
…5VDC to one end of R3
…The other end of R3 to the ANODE of the sensor
…-YHome to the Collector of the sensor
…GND to the Emitter and Cathode of the sensor
This will test for opens but still may not show an intermittent.
I will do these steps when I get home later this evening, thanks guys.
Coincidence: Turns out I am reinstalling the end stop back in my machine today after removing them so that I could trace the circuits and iverify the interface to my smoothie.
Re-assembling the daughter card and installing it on the gantry positioned the sensor so that it would hit the interposer (Its a 90 degree bracket), that is mounted in the back left on the gantry.
The interposer is not adjustable and mounts from the back of the gantry so you can’t get to it anyway.
The sensor daughter board has no adjustment either. I could get it to barely clear the interposer if I forced the board to the left on its mounts.
Not good, looks like I will have to file some slots in the sensor mounting plate so I can properly center the sensor. I wonder if any of the problems I have hard about optical sensors is this marginal alignment setup.
If I had not carefully checked this it certainly would have slammed into the sensor and messed something up.
missing/deleted image from Google+
I believe that is where all my problems began. The interposer plate was slightly out of place, thus the sensor was never “made” but rather impacted by the plate.
So my endstop is again installed. I slotted the holes in the mounting plate and now the interposer is in the center of the sensor. It was a lot of trial and error to get it aligned.
Perhaps I should have put a small led on the board to show its working?
At least maybe discussing my mishap prevented you from the same fate
@timb12957 my guess is your optical sensor if loose or damaged by the impact. We will get it figured out. BTW do you have a soldering iron?
I have used my meter to test for continuity on the traces in question. All tested fine. Yes I do have a soldering iron.