Is my power supplies dead?

So I have been fighting connectivity between my laser and my computer today, so I decided to just use a USB stick to cut what I needed cut. I went to the laser, it was on at the time. The rotary was still hooked up so I hut the emergency kill switch to shut down the laser like I do all the time. I unhooked the rotary and turned the emergency switch back on and go nothing. The display didn’t light up, nothing. The fan was still working, and I could hear the laser tube but nothing on the display and no movement from the laser itself. What do I look for to trouble shoot this? Thanks

What could you hear in the laser tube?

I’d look into the electronics cabinet and see if any of the Ruida leds are illuminated…

If no lights, I’d cycle the emergency switch… It is sufficient to power a 240V system, but isn’t really suitable for 120V, works but is on the edge.

If the fan starts running with the emergency switch then it’s apparently working.

I’d use the switches outside the cabinet if possible instead of the E switch.

On the Ruida you should have the 5V led illuminated and the run led just pulses rather slowly. If you have an ‘err’ indication, that is usually a hardware failure.

Link is a hardware indicator that your Ethernet port is connected, hardware wise.

WP1 is the coolant being active.

Make sense?

Do you have a volt meter and can you drive it?
This will open more trouble shooting options.


No it doesn’t make sense, I have no light other than a orange light on the power supply box, no lights on the main board light up

I can hear the laser tube running if that makes sense, when I cut the switch off on the side of the laser for the tube it goes silent. The fan I am talking about is the fan on the equipment door for ventilation.

Do you mean you hear coolant through the tube or the fan of the laser power supply (lps)?

It looks like you’re not getting power to the Ruida. At the top of the photo is where the 24V go into the controller from the power supply, the low voltage supply (24V).

My 24V supply has a green power light on it’s board. The yellow arrows point it out…

Can you see if yours has a power indicator…

Do you have a volt meter?

That’s probably the next step …


My green light is not lite up, is it possible that the kill switch is bad and is causing the issue? What do I test for voltage?

Since the machine has some power, such as the lps, I’d assume that E switch is OK.

You should check the output of the power supply, it will be marked gound and 24V. It should read 24V…

If it does not read 24V change to an AC scale on your meter and ensure you have 120V feeding the supply.

If it has 120V mains supply, and no output, I’d say it’s a confirmed dead supply.


So there is a yellow wire and a red wire going to the main board, which is hot and which is ground because I see no markings.

If you have a digital meter, it really doesn’t matter, the meter will read -24V if it’s tested with the leads reversed.

If it’s more convenient to measure it at the Ruida plug you can do that.

The ac mains line in has no polarity.


I’ll check it tomorrow. I’ve ordered a replacement E-switch from Amazon anyway. It’s 10 bucks, and I think it might be the issue, since this all happened when I used it to cut off the laser.

It happened to me when my electricity was off, and the sockets were broken, check the sockets please

What do you mean by sockets?

On the back or sides of the machine are ‘receptacles’ the many use for pumps/fans etc…

I think this is what he means.

If you are getting power anywhere within the device, such as the lps that you can hear running… it’s not the E switch…

Good luck


Excuse my dumbness but what is LPS?

My fault… assumptions… Laser Power Supply or lps for short… This is the high voltage dc supply that excites your tube into lasing.


Jack, it’s me again. So I’m looking at the power supply and the 24v power supply, where do I check for power?

The connections are marked on the front of the supply. You can see how they are marked as generally there is a silkscreen on the board or a label indicating the connections.

Usually on the one side or the other is the ac input. Check out this < 10 min video on replacing it. Maybe you can see where the markings on your power supply are and the arrangement.


I didn’t have time to mess with my laser yesterday, I went to look at it today and the the LSP even isn’t coming on anymore. The orange light that was on there before isn’t coming on. Before I could still raise and lower the bed, now I have nothing. The only thing that comes on is the fan that is mounted on the acess door of the power control area.

That sounds odd… The mains power come and and generally go to the lps and the 24V supply. Some have fan switches to enable ventilation. If anything is coming on, I’d think you have mains voltage to the machine.

You can check it with your voltmeter and confirm that you do have the mains voltage there and there is an intermittent connection or something like that…

Can you measure the mains at the lps and the 24V supply… they are generally marked ‘ac’…


Well apparently it was the new E-switch install, took it back out now the LPS works. Do you have a source for a new 24v +5v PS? Only one i can find its only 24v but doesn’t have the 5v for the laser pointer. I’m just going to swap it out and be done.

You’ll have to look for one… When I looked originally, I wasn’t looking for one with 5v…

Some lps have 5V line available… Have no idea about it’s current availability…

Let us know how it works out…