New 80W LPSU & tube, under performing, ammeter reads 5mA max

Machine: Custom

Board: C3D Laserboard

Firmware: I have a new board and I’m using whatever it came with

Problem/ Question:

New laser and tube, seem to be underpowered.
analog milliammeter reads a max of 5mA on a scale of 30

tested with potentiometer set at max, min, and in between values.
lower values on potentiometer lowers ammeter value, higher values, and even mid values max out at 5mA

tested using laser “test” button on the LPSU, as well as a momentary push button wired to ‘L’ & ‘P’ terminals

LPSU is 80W

attempts at trying to cut material, prove to me its power is being limited, and not a simple malfunction of the ammeter.

what could cause the laser to be so weak?
incorrect wiring?
long wire runs?
wrong gauge wires?

ill include a wiring diagram.

The diagram as wired appears correct. Can you take some actual pictures of the machine so we can verify the wiring there?

One quick thing you can try to validate the LPSU is actually getting a control signal:
With your meter on DC Voltage and the pot at 100%, what voltage do you read between GND and IN? Does the voltage change when you turn the pot? It should smoothly, linearly go from 5V at 100% down to 0V at 0%. If you’re not getting this, check the wiring at your LPSU and pot. If it looks good, try the test button on the LPSU itself: set the pot to 100%, press the button and watch the ammeter indication and see if you’re getting the power you expect.

Please report back with the findings of the above test and some detailed pictures of your machine and wiring and we should be able to debug this further.

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I know this will sound crazy, unfortunately I did it, so I know it happens…
But do you have the machine plugged into 220v? I had the same issues and found I had plugged into 110v. corrected that, and it worked like a charm.

well… i just looked at the sticker on my LPSU it says “AC input 220v”

I was pretty sure i ordered the 110v LPSU, perhaps they sent me the wrong one.

here is a link to the power supply:

just tested this, its reading 5V at 100% and 0V at 0% and changes smoothly in between

its a rats nest of wires in the box, not sure any pictures would help, as itd be impossible to follow from a picture. but i’ve triple checked my wiring against the diagram i’ve provided, they are identical.

since i don’t have a 220V outlet readily available to me, do ya think using a Transformer would help?
my K40 knockoff laser engraver came with a transformer, perhaps i could plug my new machine into this transformer.

here are some pics:

This is the transformer my K40 clone came with.

The LPSU the K40 clone came with

This is the new LPSU i purchased for my new build. the current one im working with.

found this on the product page, does this mean they don’t have two separate units for 110v and 220v?

Regarding the rat’s nest of wires, There were many pairs or bundles that were practically braided with others. I finally took a couple of hours and traced & disconnected and resoldered wires until I had a nice coherent layout. Even took the time to put in a bulkhead connector for the rotary. Does not cut any better but certainly looks better and is easy to trace wires now.

Ill probably do the same eventually, but gunna wait till i know everything is working. don’t wanna make everything nice and tidy, if i have to rip it apart again to diagnose a problem.

As far as I know, correct. This type is fixed input voltage. Where are you located and what is your normal mains voltage?

Alberta, Canada, 120v is the standard at wall outlets

Then yeah, in general, using a 220v rated psu on 110v power can certainly be a reason for lower power output.

in the picture above, the LPSU says 110v/220v (optional)

does this mean the unit can be switched to use 110v?

if not, can i use the transformer ive posted above?

Without knowing the psu it’s hard to tell. If it is switchable from 220 to 110, there would be a switch or perhaps a jumper on the exterior or even interior of the psu. If nothing is obvious, you probably just ordered the wrong one.

If you can’t return the psu for the right one and there is no way to switch or convert it to 110, I would use the 110 to 220 transformer to step up the voltage to 220. You just need to make sure the primary of the transformer is connected to the 110. If you are not sure which winding is which, an ohm meter will tell you straight off. The primary winding will have a much lower resistance.

Before you send power to the machine, plug in the transformer with what you think are the primary and measure the output voltage. If you have it connected right, it will read 220 and you are good to go

A word of caution, if there is anything else on the machine that normally is powered by 110, you need to make sure you don’t fry it if you feed 220v to the whole machine. For example, if the 110v power supply to feed the dc to the c3d board is not dual voltage and you put 220 to it you will fry the C3D board

Check your order and confirm the mistake isn’t on their end. If it is get them to exchange it. If you feel the mistake is yours then go down the route of trying to get a solution if you don’t just want to get another and try to sell the one you have on eBay or something.

well, took the transformer from the old K40 clone, and added it to the new machine, solved the problem. thanks for the help.

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