Well. That is surprising…
Hi Kinan,
You’ve had a frustrating time. I have a next step and I’m sorry I did not think of it sooner. Someone should run your g-code on their (same/similar) machine to see if it exhibits the same problem. I have a Rambo 1.4 and dual end stops. Unfortunately I’m out of town for the holiday. If no one else gets to it, I’ll be glad to run your g-code on Monday evening. This would be a very telling test.
Also I wanted to make sure you ran your SD card test with all non-essential cables unplugged from the control board including the USB cable and the dual end stops wiring.
Your gcode is set to 6 decimal places, that is too much. Two is fine, three is pretty serious. There is also no reason to send Z0 with every command. I think you are just flooding the planner.
Also whatever you are using to generate it check your accuracy setting, maxing that out is unnecessary.
The crown test is the best way to test new firmware. I am seeing this as a CAM problem/accuracy overkill. Best guess. Try the crown if that doesn’t work we have an issue.
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You are also trying top run at 65mm/s. The firmware is limited to 50.
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Hello, @vicious1, @jeffeb3 , I really appreciate your answers! I mentioned a few things in an earlier post perhaps I need to repeat it to make some stuff clear:
- The exact same Gcode used to work perfectly without any issue on my older set up ( Some older version of Marlin, series wired and without dual end-stops.
- I already did the crown test and had the exact same issue.
- I printed these tests from the Sd card and removed the serial Cable and the endstops as well in order to maybe easily identify the issue as @robertbu suggested.
I modified my Gcode anyway as you suggested and made a small test again. The average line Segments length is 1.5mm which i think is totally fine. I even removed the Z0 and reduced the speed. This didn’t change anything at all. I attached two videos and Gcode, one for a freeform curve and the other for a circle. It is really hard to detect any pattern at what time this delay is happening, seemed like it doesn’t not really have anything to do with the geometry, because when i send the same Gcode again it happens on different positions. The weird thing is when drawing a circle it might happens only 3 times for the first half and then it works perfectly, which does not make any sense for me.
Here is the Gcode i am not sure how helpful it is to run it on your own machines, it is possible to print on 500x500 Cnc machines.
Please pay attention to the sound in the videos!
This issue is driving me crazy! I would be very thankful for any help !
Freeform test
Circle test
Fixed Gcode Lattency Issue 2 tollerance 0.01.gcode (21.3 KB)
It must be ghosts. 
Did you have repetier host connected when you were running from sd card?
When, approx. did the original working firmware come from?
Are you on v508 of the new software?
Experimentally, this all points to some bug in Marlin in the latest firmware. But what is getting me is, this firmware has been tested with the rambo and we haven’t seen this issue.
It is best to stick with the test crown then for any tests as this has been extensively proven to work, fits on all builds, and is fairly quick. So we can all test the same thing, rule out any CAM or CAD on your end. I am not sure if I will get any work time in today but will try it as soon as I can. As this could be part of the laser issue I am seeing…but For me it is a speed thing. I can slow down and it goes away, I use the lasers as fast as possible.
Jeff’s questions are solid, waiting on those.
haha, ghosts seem to be the most logical answer after this hassle 
No, as I mentioned I removed all the unnecessary cables including the USB Serial. I tried flashing the last 4 releases of Marlin`s firmware (V508 2.0.7.2, V507 2.0.7.1, V5.6 2.7, V505 ). I bought the parts in mid-2019 from V1 Engineering. If it were a bug, then how come that you guys never heard of this issue before? I am so confused!
All four of those releases do not work with the crown? I have tested most of those on a Rambo with the crown and seen no issues.
If that is the case we are looking for something like a bad connection. Looking at your first picture I would start by removing the power adapter you have on there and plug it in directly. The little plug to two wire terminal on your power connections is a know weak point. Cut your power wire right behind the barrel connector and hardware it like I have shown in the instructions.
The other thing to try is isolate your LCD cables from everything else. If they are bundled with the stepper wires like it seem to be in the first picture you could be picking up line noise.
Hey Ryan! Thanks for the tips.
I have tried wiring the Power connection as you have shown, I also separated the Lcd screen from the Stepper Motor wires but it didn’t change anything again.
Should I keep the Stepper motor wires bundled or this could a problem as well?
Hey Ryan,
I forgot to mention that speed doesn’t change really a lot. I tried to run it at the slowest speed, the jittering would still occur.
This is getting me crazy, almost two weeks trying to understand the problem.
What does this mean? You made new Gcode that was running at 5mm/s or something?
This is a problem like we have never seen before. I have no idea how or why this could even happen. So we have to go through this step by step.
You have tried everything with the SD and LCD so no lets try unplugging the LCD completely and run my crown gcode from the computer over USB.
No, I didn’t really generate a new Gcode. I decreased the speed through the LCD Screen/Repetier host.
I have tried everything twice with and without an LCD screen. Exact same result. Just realized that with the Crown test the delay happens on the longer curves. I am not sure if this help.
@vicious1 @robertbu Here I attached a video of the Crown Test. Maybe this can help Crown test
Current Marlin version is V506 2.0.7
Also some pictures of my actual setup…
From the video it looks to me like the frame of the machine is what is shaky. Are you sure all the corner connections are tight? Could you add some temporary diagonal bracing to see if that stops the shaking?
No the Whole table is shaking as it stops in between, which makes the camera shake as well.
The frame is pretty stable.
I have no idea how this would even happen.
1-Can you make sure to use the LCD advanced configuration menu and initialize eeprom. There could be a persistent setting in there. Another thing to try is swap the ribbon cables on the LCD maybe one is bad, each side uses different wires (but if it happens over USB without the LCD plugged in This should not be an issue).
2-Maybe pull the board out of that box and hit it with some canned air to make sure there is nothing touching where it should not be.
3-Can you make sure your power supply is hitting 12V (11V-13V) cleanly and not fluctuating very much.
4-The reset button is not touching the side?
I will flash 508 when I go out to the shop in a little bit and double check the crown gcode on my build just to be certain.
I though this question had moved beyond what I had to contribute, but since it is still not solved, I decided to follow through with running g-code on my machine. What I found was interesting. I have a Rambo 1.4 board and am running Marlin 427D headless.
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Running Kinan’s Latency delay troubelshooting test Tolenarnce 0.002mm.gcode - It jittered on my machine exactly like his video.
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Running Kinan’s Latency delay troubelshooting test Tolenarnce 0.055mm.gcode - It jittered also. The jittering was regular, almost like it was pausing at the end of each line segment used to emulate the curve.
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Running the crown test g-code Ryan authored - I believe that it happened occasionally. Given the much smaller movements and the legitimate reasons for deceleration, it was difficult to tell.
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Estlcam authored enlarged crown - I created a crown much larger than Ryans. I saw the occasional pause on long arcs where I would not expect a pause. It wasn’t a jitter, just occasional places on a continuous arc where I could hear the steppers wind down and it could see the tip of the bit pause just a bit.
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Fusion 360 authored curve - I authored a large closed spline in Fusion 360 - I noticed a pause in just a few places…fewer than the large crown test.
Some observations:
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Given that it happens on my machine running headless without any USB cable, it point away from any kind of electronics issue specific to Kinan’s machine.
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Kinan’s g-code has 6 digits after the decimal point, Ryan’s crown and the enlarged crown had 4 digits after the decimal point, and the fusion 360 generated g-code had 3 digits after the decimal.
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I cannot see these pauses from EstlCam or Fusion generated g-code being noticed when using a router, but they might leave an artifact when using a laser.
Is it possible that newer versions of Marlin just have more overhead and therefore less processing time for floating point calculations? I love to see this test run with an old version of Marlin.