I have removed the original electronics of my K40 laser and I have put a MKS DLC 2.1 controller board, I have followed several schemes that I have seen on the internet and I have connected it in the following way:
Currently I have the LPS out since I have enlarged the laser and made a 3D printed box for it. I have changed the electronics for an MKS and the laser cathode comes out from the L- pin to the ammeter and from the ammeter to the laser and the positive comes out directly from the LPS.
The power supply led turns on and the fan also turns on.
In IN I have 5V which is provided by the original potentiometer.
I have nothing connected to pin L of connector P3.
Do I have to make a jumper from the L pin of the P2 connector?
The FG pin must be in contact with the metal case of the laser?
Ok this generally means you have AC and low voltage.
Did you measure 5V on IN?
So with IN at 5VDC the test button does not fire the laser, right?
The test button bypasses all the controls but IN. So if the laser does not fire with the Test button and IN is at 5VDC then L is academic. The test button does the same as L but it does it internally.
Your laser has a metal case???
In any case FG should be connected to the frame and would not cause this problem.
Tell me about the machine and LPS history:
How hard has it been run?
Has the tube overheated?
How old is the LPS?
What kind of coolant are you using?
Have you seen/heard any arcs, hissing or crackling.
In case you are not aware the output of the LPS is LETHAL so stay far away.
The challenge is that this problem can be a bad LPS or a bad tube or both and there really is not a safe way to tell which. Therefore we check everything around it to verify it is working.
Generally if the tube is bad and the LPS is good you will get arching.
My guess is that your LPS is bad but I will wait for the answers to the above…
Don answered that in his long point by point reply… you need the IN control set to some voltage and it’s expected to be set with a POT connected across 5V and ground with the wiper connected to IN. Or you can hardware IN to 5V and blast the laser at 100% power.
Use a CW-3000 “water chiller.” There are lots of these on ebay for US$150 and up, marketed for cooling lasers. The problem is that they are not chillers. They are radiators that blow room temperature air over your cooling water. If your water is cooler than room temperature they will actual heat your cooling water.
FYI, that is not coolant( water, antifreeze, alcohol, etc ). And also the CW-3000 is only a room temperature heat remover and since you need to keep your “coolant” below 25C(77DegF) than your room MUST be at some temperature below 25C for there to be any heat removal from your laser cooling fluid. The CW-3000 is not an active cooler, just uses room air blowing over fins.
Note: 25C is the temperature at which you should shut down your laser. You want to operate your laser at close to 20C.
BTW, there is a link at the top righthand side of this page called K40 Intro and you should read every section in it. You would have known about cooling and many other aspects of the K40 from safety, setup, normal operation and customizations. Since the K40 is not a consumer product it can not be stressed enough that this document should be read from front to back before operating the machine. New to K40: Start Here