Chinese K40 laser cutter fix - Mar 2025

Chinese quality at it's finest

DESCRIPTION

I wanted to cut some parts for a light fixture that I am making.

See here

The laser cutter decided that I would not be able to make my parts and made its best attention whore impression.

Last time I had used the laser, it worked fine but now I was unable to move any axis on my machine.

After checking the obvious, I changed the usb cable and the cutter would still not be visible to the computer, this was weird.

I took measurements on the power supply part of the board and found nothing wrong.

The internals of the laser cutter

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After banging my head several times on the wall, I decided to take the board off the chassis.

My actual driver board

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After some light probing, I found out that my board did not get power from the USB connector for the usb controller, instead it used the 24v input from the board for some reason.
IMHO 3.3ohms for a fusible resistor is pure madness.

Board probed, 5v for usb controller in red

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Chinese engineers for some reason

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After re-evaluating my life decisions, I began thinking that my initial assumption might have been correct and all of this may just have been some loose connection…
What was really odd is that I had the proper voltage at the connector but when I probed the board while it was plugged in, I measured a very low voltage.

SOOOO, I tried to pull on all connections inside of the machine.

AND THEN

Told ya about chinesium crimped connections.

The true culprit

demo_photo

And God said

“Let there be light”

and there was light

After changing this “crimped connection”, it works once again…

WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY, WHY DOES THIS KIND OF STUFF ALWAYS HAPPEN WHENEVER I FIND THE MOTIVATION TO DO SOMETHING…

EVERYTHING_IS_FINE

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