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PSU not driving laser to rated power

PostPosted: Thu Nov 09, 2017 11:26 pm
by Tklus
Hey Guys,
Just getting my laser up and running... finally... been a year and a half project...

I am using the LO-x7 DSP and a laser power supply and 40w tube from coletech on ebay.

when driving the laser at 98% I am only getting 9.4 milliamps on my amp meter.

when cutting 1/8 ply, I have to run it at 7mm/sec to cut through. I was reading an article that said you should be able to cut 1/8 ply at around 14mm/sec. this indicates to me that my amp meter is probably true and I am only getting about half power out of my laser.

I checked the PWM output from the controller and it is putting out 4.88 volts at 98% power. this seems about right.

My question is, could it be that I was sold a 220v power supply and not a 110v supply. the ebay listing did state 110v input but there is no markings on the PS that indicates voltage. is there an easy way to tell what the voltage of the PS should be? I will attach some pics of my PS and voltage inputs. anybody have similar experiences?

Thanks for the help!

Re: PSU not driving laser to rated power

PostPosted: Sat Nov 11, 2017 12:30 pm
by Techgraphix
Tklus wrote: is there an easy way to tell what the voltage of the PS should be?

Ask your seller (Coletech) They could tell you where to look and how to check the right voltage (which can be a switch or jumper inside, or some component-label)
Once i had a supply that was set 115V while we have 230V here.. Some smoke and a blown fuse made it quite Obvious that this was the wrong supply..
I doubt a 230V supply on 115V will work stable anyway, but it can.
for 40W a current of ~18mA should be normal.
If you have someone with a laser-power-meter in the neighbourhood, you might borrow it..


Re: PSU not driving laser to rated power

PostPosted: Tue Nov 14, 2017 3:23 am
by Tklus
So I opened up the power supply and found some potentiometers but have no idea which ones to adjust. I am seriously considering just buying a ps from light object and being done with this

Re: PSU not driving laser to rated power

PostPosted: Tue Nov 14, 2017 10:17 am
by Techgraphix
To see if this supply is 230V or 115V, you only have to look in the first part of the supply.
I expect it to be as the attached schematic diagram

On the left you enter the mains (115 or 230V) then it will pass the fuse and the filter (on your photo the small transformer with the double coil on white plastic) from there it will go to the rectifier (the rectangular black block that is placed in an angle). from there the PLUS and MINUS will go to the electrolytic capacitors. (those big black cylindrical things in the middle)
BEWARE!!! those Elco's can hold leathal charges!! measure before you touch anything!
If this supply is 115V there should be a connection (a jumper or a wire/bridge) between the centretap (where the two elco's are connected to eachother) and one of the AC-inputs (~) of the rectifier.
In the diagram this is the green line.
If there is no connection, you probably have a 230V board. You might find a pair of holes in the PCB with a white printed line that could connect the centretap and AC-input.
I ommited all extra components in this diagram as their only function is to protect or suppress (filter)
Normaly the fuse will be rated higher for 115V. Maybe this value is printed on the PCB. Say, it should be 1.6At for 230V and 3.16At for 115V use. If there is a 1.6At fuse placed, then you probably have the wrong board (these values where just an example!)

Succes and be carefull!


Re: PSU not driving laser to rated power

PostPosted: Tue Nov 14, 2017 8:52 pm
by Tklus
Thank you for the info. I will check it out.

One other test I did last night was to check the output on the 5v on the laser power supply. This output was 5v with a 110vac input.

If this was a 220 board, should I have gotten 2.5v out of the 5v terminal?

There was a guy in YouTube that was having a similar issue and it turned out to be a bad flyout transformer.

Thanks again for all the help

Here is a pic of the bottom side of the board