Bad USB connection on a 40W Falcon-2 Pro

Ever since I got the machine, it has had a flaky USB connection, and now it does not work at all. My problem appears to be the same as shown in this video:

Creality Falcon 2 new, out of box faulty USB ports:
https://www.youtube.com/watch?v=imTJljqGe7s

and here is a post with most of the details on tracking things down:

Falcon2 40w the air pump will not turn on:
https://forum.creality.com/t/falcon2-40w-the-air-pump-will-not-turn-on/41040/3

I later also noticed that the USB was no longer showing up on my laptop’s system tray when I plugged it in. As a note, the connection was always flaky, but now it is not working at all. At this point, I have only been able to cut some cardboard test pieces, and the machine has not even made a single real cut.

As a note, I did a number of other things, like clean the lens, clean the air filter, swap multiple cables, etc., but nothing seams to be working. But for running the machine for maybe an hour or two total cutting some cardboard, I have not done any of the jig making work that I purchased the machine to do. It would be great if someone could help me sort this out.

Oh boy, do I have a weird tale for all of you. I mostly got it working again, but there are some subtle details that points to a design flaw in the controller…

Problem #1: tower power strip with banked switches…
I have really nice power strip that has 4 banks of 4 power plugs, each bank of 4 has its own switch. So, I am able to dedicate a bank of power switches, and turn machines and equipment via a single switch. The tower I was using has a bunch of equipment plugged into it, and apparently with everything running at once, the Falcon-2 power brick was apparently not producing enough juice. I figure this out when I plugged the equipment into a different power strip that only had the Falcon-2 on it. So with a dedicated power strip, or plugging it directly into the wall, I got it mostly working, but…

Problem #2: laptop supplying power to the controller, via the USB, before the main power is turned on…
We all have come to expect USB-C PD to just work, but in this case if the controller is first connected to a USB-C PD port, it will provide just enough power that the CPU on the controller starts up, but there is not enough power to properly configure itself, and it goes into lala land – and unplugging/plugging the cable does nothing. The trick I found that mostly works is to power down the Falcon-2, disconnect the USB cable, turn the power back on, and after the controller starts up, plug the cable back in… Ok… it is working more often than not… Creality needs one of their electrical engineers try cutting the trace from the USB-C PD output on the controller, so that it only starts up with power from the power brick. If this works as expected, the cut trace could be included in the next revision of the controller board. I mean if we think about it for a moment, we are likely never going to be able to run a 40w laser cutter from a laptop’s USB-C PD, so cut the trace. It is also unreasonable to expect yjsy modern computers support USB-C but without PD…

Problem #3: loose/ill-fitting USB-C port…
As seen in the video I liked to above, the USB plug is loose and wobbly. This is likely some minor design flaw, and resulted in me seeing the LED status lights fade when I jiggled the cables. Without opening up the module, I can only guess what is happening on the board, but it is likely going to eventually break…

Overall: I consider the USB-C PD bring the controller up in a unstable state a design flaw. Likewise, having the port plugs be unsupported and wiggling is not only a design flaw but possibly a mission-critical safety issue.

Workaround: To get it to startup and work consistently I have to unplug the USB-C cable, supply power through the brick, and then attach the USB cable. Once it is one in this sequence it works roughly as expected, BUT I make sure that the brick power supply is unplugged after each use, and I will be wroking on a way to cable-tie the cables to the machine (so they cannot be yanked out by accident – and possibly breaking the plugs.

So, I hope that others from my hardware sluthing useful…

Earlier today I also realized that the USB-C PD issue might be fixed by a chip specific firmware update – if the microcontroller or USB chipset allows you to turn off the PD from firmware. I do not know which chipset this controller uses, otherwise I would look it up and point you to an appropriate reference.

I will probably feel like a complete idiot when you answer this, because I probably already know very well…

But you are referring to “USB C PD” several times… what do you mean by this?
I’m well aware of what USB C is, but what do you mean by “PD”?

Not a stupid question at all. PD stands for"Power Delivery" (see: USB hardware - Wikipedia). I should have written it out long-hand the first time I used the acronym. Sorry for the confusion.

Aaah okay, so we’re talking about the power delivered through the usb cable, and the respective computers ability to deliver enough power to the controller through the usb port…?

So if I understand you correctly the issue appears when a computer is unable deliver enough power through the USB ports, because of how the controller is designed and built, the controller needs a certain minimum amount of power to do it’s thing and connect properly…?

I’m not sure if this is the issue in my case but it definitely could be…

I own a Falcon 10W and I cannot for the life of me get it to connect to the computer… AT ALL…

I have tried to connect the usb cable after I turn on the Falcon and I’ve tried connecting the USB cable before I turn on the Falcon…
I’ve tried with multiple different USB C cables and USB ports.
I’ve tried uninstalling the software and I’ve even tried a different computer, but absolutely nothing happens…

When I connect the USB cable I can hear the sound response from my computer that something was connected but there’s just nothing to choose from in the “port” drop down menu and after a few seconds my Falcon will go into standby mode…

Whether I’m trying to connect to Lightburn or LaserGRBL makes no difference…

I’m completely at a loss at this point…

Close. The issue is that when you hook up the computer, and it tries to power the laser controller, but the power is turned off to the laser’s regular power supply (the brick), the controller gets confused and will not come back without unplugging everything. The dance steps I use to get it working are to power up the machine with its regular power supply, and then attached the USB cable.